Railway Switch and Crossings – How train change the track?

Railway Switch and Crossings – How train change the track?

 

Railroad track Crossing is the most important steering system in the railroad track. It consists of two parallel steel rails set a fixed distance the standard gauge is 4 feet 8.5 inches.

In the track change process, the inner rim of the wheel called a flange is comparatively greater in diameter than the outer part which prevents the wheel from sliding off the track.

Switchs:

Switch rails or point blades are the movable rails that guide the wheels towards either the straight or the diverging. Track stock rails are the running rails immediately alongside the switch rails against which the switch rails lay when in the closed position points operating rods.

Point blades

Stock Rail

Points operating machine also known as a point switch machine or switch motor is a device for operating railway turnouts especially at a distance.

POE Rods

Points Operating Equipment

Crossing:

Crossing is a pair of switches that connect two parallel rail tracks allowing a train on one track to cross over to the other check rails also known as guard rail laid parallel to a running track to guide the wheels. All these rails are non-movable.

Rail track Crossing

Crossing nose as a device on introduced at the point where gauge faces cross each other to permit the flanges of the railway vehicle to pass from one track to another.

Crossing Nose

The Main Railway Track Components

The Main Railway Track Components

 

The distance between the two tracks on any railway route is known as railway gauge. The wooden or concrete supports for the rail tracks are known as a sleeper as British English or cross tie as American English.

Railway Gauge

Sleepers:

A sleeper is a rectangular support for the rail tracks. It is laid perpendicular to the rail sleepers and transfer loads to the track ballast and subgrade.

Sleepers hold the rails upright and keep them spaced to the correct gauge.

Sleeper

Railway Fastening System

Ballast:

Ballast is the name for the stones beneath the track. It forms the track bed upon which railroad sleepers are laid and is used to bear the load from the railroad ties to facilitate drainage of water and also to keep down vegetation that might interfere with the track structure.

Railway Ballast

The ballast also holds the track in place as trains roll over it and absorb the noise. It typically consists of a crushed stone rail fastening system. It is referred to as a group of railway fasteners that are used to fasten steel rail to railway sleeper.

Fish Plate:

Fish plate is used to join two different rail tracks without welding leaving some gaps at the joining of the track so that when they get heated it doesn’t bend. There are foor bolts that hold up the tracks together.

Fish Plate

Rail Track GAP

There is another type of fish plate called juggled fish plate. This is a specially designed fish plate with convexity in the center to accommodate weld collar at newly welded joints to protect defective welded joints and to carry out emergency repair of weld failures.

Joggled Fishplate

The Main Materials Of Ties Used in Railways

The Main Materials Of Ties Used in Railways

 

The purpose of the tie is to cushion and transmit the load of the train to the ballast section as well as to maintain gage.

Wood and even steel ties provide resiliency and absorption of some impact through the tie itself.  Concrete ties require pads between the rail base and tie to provide a cushioning effect.

Ties are typically made of one of four materials:

  • Timber
  • Concrete
  • Steel
  • Alternative materials

 

1. Timber Ties

 

It is recommended that all timber ties be pressure-treated with preservatives to protect from insect and fungal attack.  Hardwood ties are the predominate favorites for track and switch ties.

Bridge ties are often sawn from the softwood species.  Hardwood ties are designated as either track or switch ties.

Factors of first importance in the design and use of ties include durability and resistance to crushing and abrasion. These depend, in turn, upon the type of wood, adequate seasoning, treatment with chemical preservatives, and protection against mechanical damage. Hardwood ties provide longer life and are less susceptible to mechanical damage.

Hardwood Track Ties

 

2. Concrete Ties

 

Concrete ties  are rapidly gaining acceptance for heavy haul mainline use, (both track and turnouts), as well as for curvature greater than 2°. They can be supplied as crossties (i.e. track ties) or as switch ties. They are made of pre-stressed concrete containing reinforcing steel wires. The concrete crosstie weighs about 600 lbs. vs. the 200 lb. timber track tie.

The concrete tie utilizes a specialized pad between the base of the rail and the plate to cushion and absorb the load, as well as to better fasten the rail to the tie. Failure to use this pad will cause the impact load to be transmitted directly to
the ballast section, which may cause rail and track surface defects to develop quickly.

An insulator is installed between the edge of the rail base and the shoulder of the plate to isolate the tie (electrically). An insulator clip is also placed between the contact point of the elastic fastener used to secure the rail to the tie and the contact point on the base of the rail.

 

Concrete Track Ties

 

3. Steel Ties

Steel ties are often relegated to specialized plant locations or areas not favorable to the use of either timber or concrete, such as tunnels with limited headway clearance. They have also been utilized in heavy curvature prone to gage widening. However, they have not gained wide acceptance due to problems associated with shunting of signal current flow to ground.

Some lighter models have also experienced problems with fatigue cracking.

 

Steel Track Ties

 

4. Alternative Material Ties

Significant research has been done on a number of alternative materials used for ties. These include ties with constituent components including ground up rubber tires, glued reconstituted ties and plastic milk cartons.

Appropriate polymers are added to these materials to produce a tie meeting the required criteria. To date, there have been only test demonstrations of these materials or installations in light tonnage transit properties. It remains to be seen whether any of these materials will provide a viable alternative to the present forms of ties that have gained popularity in use.

Cool Reflections for Overheating Metros!

Cool Reflections for Overheating Metros!

“Why paint trains with high-performance solar reflective paint ……….and fit low emissivity glass windows?”

Author: Calvin R Barrows, BSc (Hons), CEng, MICE

 

(N.B. The focus of this article is on mixed surface and sub-surface Metros like London Underground. Many of these, like London Underground, do not have sub-surface cooling systems throughout.)

There are many heat sources in Metro systems. However, only those that are seasonal are under consideration in this paper. Indeed, it is worth noting that, in the cooler weather the combined effect of the non-seasonal heat sources is insufficient to heat trains to a temperature in which customers would feel comfortable and so in winter these heat sources need to be augmented by the addition of heating from train saloon heaters.

However, there are two heat sources that increase in summer: outside ambient air and solar irradiation. The former is an important and notable seasonal variant, but whilst ambient air temperature varies throughout the daily cycle, it does not dramatically change over a 30 minute period. It cannot, therefore, explain the cause of the considerable increase in train temperatures on the surface often achieved over that same time period, so this paper will focus primarily on the role of solar irradiation.

Even though we all experience the effect of sunshine in summer, there does not appear to be more than a superficial appreciation of just how powerful solar irradiation can be! In this link, under the “Measurement” section it explains that “…direct sunlight at Earth’s surface when the Sun is at the zenith (directly above) is about 1050 W/m2”.

This is generally supported by the monitoring and other evidence presented in my article “Cooling the Tube – On Ice till 2030”, and also by the fact that in the summer of 2018 my pale coloured sandstone patio was as red-hot as the sand on a Mediterranean beach.

However, the sun’s power is also affected by the Angle of Incidence, which reduces its intensity when it is at shallower angles. For example, at a 450 angle of incidence, although solar radiation can cover a 40 percent greater area, it is then 30 percent less intense than when at its maximum angle of incidence of 900. Consequently, we also need to consider how this changing intensity might affect trains.

Prof. Piercarlo Romagnoni and Prof. Fabio Peron of the Università Iuav di Venezia produced a factsheet which examines the temperature impact solar radiation has on thermal insulation materials in roofing applications. Although some train roofs are not insulated, this factsheet gives an indication of the potential external skin temperatures.

One test they undertook was on a roof sheet formed of a curved sandwich panel:

  • The external surface was aluminium metal sheet, thickness 7/10mm, painted red;
  • The insulation layer was a 40mm thickness of polyurethane foam;
  • The internal surface was a galvanized, corrugated metal sheet, thickness 4/10mm.

Whilst this is not exactly how a train roof is constructed, I would submit the external skin of a train roof would absorb similar levels of solar irradiation and reach similar temperatures. The maximum temperatures on curved roofs in more moderate climate zones like Venice can reach 67°C. Summer ambient air temperatures in Venice can reach 40°C, so the surface temperature of the aluminium external skin of this sandwiched panel is potentially around 25°C above ambient, which is akin to the difference between train rail temperatures and ambient air temperatures.

The next consideration is, how much of the train should we coat with solar reflective paint? Some railway staff have focused on the roof. However, focusing on the roof alone will limit the potential benefits.

The average carriage size is 2.9m wide with a “passenger compartment” body height of around 2.5m. Taking that as a basis, when the sun is at its zenith, it produces 1050 W/m2 x 2.9m per metre length of carriage or 3045 W/m (3.045 kW/m) on its roof.

However, with the sun at an “angle of incidence” of 450 and hence with the sun on both the roof and one or other side of the train, there is approximately 2.5m + 2.9m of train body exposed to the sun. At this angle the sun’s intensity is 1050 W/m2 x 70% (30% less than at its zenith) = 735 W/m2 but this is now shining on 5.4m per metre length of train body. In this scenario then the sun produces 735 W/m2 x 5.4m per metre length of carriage or 3969 W/m (3.969 W/m).

 

The 1972 British Rail Research calculation [abstract], had previously raised a concern about the challenge of how solar irradiation can be calculated. TfL have kindly provided figures from the original, full report (which no longer appears to be directly available in the RSSB’s SPARK Rail Knowledge Hub’s archive). The process of arriving at these figures, as set out in the abstract, appears completely unintelligible and this historic calculation of 7.8kW per trailer car or approximately 0.5kW per metre length of carriage, is clearly way off the mark for the following reasons:

  • Train saloon heaters for winter operation produce around 15kW of heat per carriage, approximately twice the 1972 claimed power of the summer sun!
  • Even in low ambient winter temperatures one’s body can be pleasantly comfortable when in the
    winter sunshine.
  • Recent posts on TfL’s Yammer Network about a trial investigation on the Central Line were brought to my attention. This investigation compared the levels of solar heat gain through saloon windows fitted with tinted film to those without, and the extent to which untreated windows contributed towards the elevated temperature in the carriages, in open sections of track, during the hottest portion of the day. A significant temperature difference was recorded, the saloons with the tinted glass windows being up to 4.50C cooler. The limited, low performance measures implemented by the year 2015 would only have delivered these notable improvements, if the effect of solar irradiation were significant, which it clearly is!

Let us now consider the benefits of using high-performance solar reflective paint on train bodies. The trials undertaken by the Australian Navy on their patrol boats have shown that the low solar-absorbing formulation reduced their surface temperature by 15-200C compared to conventional coatings, and consequently lowered the power load for on-board cooling systems. In the context of metro trains, reflecting the solar irradiation would:

  1. Reduce the train’s internal temperature in summer;
  2. Reduce the required size of the air conditioning, delivering greater payload and reduced weight;
  3. Reduce the in-train air conditioning running costs;
  4. Improve the passenger experience in terms of comfort; and very importantly,
  5. Reduce the safety risk to passengers in a stalled train event.

Similarly, in the context of reducing tunnel heat, reflecting the solar irradiation when travelling on the surface in summer would:

  1. Reduce the train’s external skin temperature; which in turn will reduce the absorbed heat load into the train body and thus the heat emitted from the train body into the tunnel;
  2. Reduce the train’s internal temperature, and consequently reduce the heat being discharged from the train’s air conditioning (if fitted) on entry into the tunnel; and
  3. As a result of 1 and 2 above, subsequently reduce the heat transferred across the network from hotter lines to cooler lines by the “pressure / suction” wave caused by the movement of trains, whilst satisfying the Laws of Thermodynamics – heat will go to cold.

However, it should be noted that the benefits do not stop there ….. For tunnels with adequate and comprehensive cooling systems, with the use of solar reflective paint these systems may become less crucial, be under-run or even become fully or partially redundant. For those where such measures have not already been installed, solar reflective paint may obviate the need to install them at all.

As obvious as all the above may be by now, testing still needs to be carried out. Whilst it is simple to compare the reductions in internal train temperatures, accurately assessing the cumulative reduction in tunnel temperatures as each train is treated is less straightforward.

Testing should involve the continuous temperature measurements, along its route, of all the relevant train temperatures and be related to time, location and external ambient temperature: but there are several things that will need careful consideration in order to quantify accurately the collective benefits in respect of reduced tunnel temperatures. The sooner these relevant train temperature readings can commence the sooner a reliable baseline can be established.

Undoubtedly the optimum test would be to treat all the trains on one line, and I would suggest the most appropriate line would be the Central Line, especially bearing in mind the 40+0C temperatures experienced this last summer (2018). Doing this optimum test would be the only way to measure, rather than theoretically predict, the overall reduction of tunnel temperatures. It would not be deemed sensible to treat all the trains without some evidence of the benefit; however, the limitations of data from a less comprehensive test will need to be fully understood and well thought through.

Such a comprehensive test would also avoid skewing the results with such elements as the carry-in heat of untreated trains being transferred within the tunnel, to the treated trains – we have a possible Catch 22 situation here!

Monitoring the winter temperature would be useful to compare the train’s external skin temperatures with those in the summer. On the face of it, there would seem little to be gained monitoring internal saloon temperatures with their heaters operating. However, it is yet another legitimate cyclical heat source to be considered within the seasonal differential and I believe it would be useful, provided it is interpreted appropriately. Unlike the practice to date, ALL possible heat sources should be robustly accounted for!

Monitoring the train’s external skin might best be achieved with sensors on the internal face of the external skin, suitably insulated from the train’s internal space. This will mitigate the inaccuracies caused by unrepresentative cooling effects – e.g. local eddy currents caused by turbulent air flows, which have certainly proved difficult in the context of modern cars. Monitoring of undercarriages and bogies would need some serious thought, in order to be able to identify the effects of the various heat sources operating on these – see below.

However, with every further treated train, first on the Central Line and then throughout the network, the cumulative reductions on tunnel temperatures, and thus sub-surface network temperatures would become significant. Hence the fullest benefits will only become apparent when all lines, with the possible exceptions of the Victoria and the Waterloo & City Lines, have had all their trains treated.

Whilst the foregoing looks at the general solar irradiation effect on the passenger compartment of the train, it should not be overlooked that the undercarriage (bogies) will also be affected. Two NON- seasonal heat sources acting on these are obvious: traction and braking. However, there are three seasonal ones that need to be considered and the overlooking of these may have skewed the previous perception of the heat load from braking.

  1. The considerable mass of steel in the bogies and wheels, which will be affected when the sun is
    striking one or other side of the train;
  2. The heat being constantly emitted / transferred from the rails, which in the summer sun can often
    reach 20°C above ambient; and
  3. The solar irradiated sleepers and ballast, which will also absorb the sun’s heat, reflected to the
    underside of the train and bogies.

These additional heat loads are less likely to have a significant effect on the passenger compartments when overground but will add to the carry-in heat within the tunnels and so it would make total sense to treat the exposed areas of undercarriage and wheels with the high-performance solar reflective paint.

It should be noted that more recently Railtrack have been painting non-wearing exposed surfaces of rails with white paint to mitigate rail buckling. Additionally, implementing this on London Underground will reduce the heat absorbed by the rails and consequently what they “emit” when the train passes over them.

In considering the issues raised in this paper, clearly painting the train body and undercarriage in this way is still only part of the solution, albeit a significant one. In addition, there is the matter of the windows, which at present is a crucial factor in turning carriages into “greenhouses”.

The effect of solar gain through glass windows into a room (aka a carriage) is well illustrated. The next logical step
to the use of high-performance solar reflective paint would be to fit “low emissivity glass” windows in all trains.

Managing the two-way passage of heat through glass has come a long way with Low-E glass. Given the high percentage of window glass in the body of a carriage, using this highly reflective glass meansthat the external solar heat will not be absorbed whilst the train is on the surface (as with solar reflective paint) and so:

  •  the internal carriage temperatures will be reduced; and
  •  the external glass surface temperature will be reduced, which in turn will reduce the carry-in heat being emitted when the trains pass into the tunnels.

Treatment with solar reflective measures would probably be best undertaken in stages:

  1. Establish the baseline for tunnel temperatures with “all trains being untreated”;
  2. Treat one train, including the undercarriage, initially with high-performance solar reflective paint
    and low emissivity windows;
  3. Compare the reduction in heat absorbed by this treated train with the baseline data;
  4. Extrapolate the above results to get a sense of the cumulative reductions in tunnel temperatures that can be achieved once all trains are treated.

Clearly treating only one train will have a negligible effect on tunnel temperatures but treating all the line’s rolling stock will achieve a significant reduction in tunnel temperatures across the treated line.

Some insight as to the consequences of heat emittance on the treated train from the untreated trains in the tunnel would also be useful, since such a transfer of heat would result in an under-estimation of the ultimate benefits. However, by virtue of an inefficient transfer mechanism, the effect of overheated tunnel air on the treated train skin may not be of great significance.

Of course, when the temperature of one line (the hottest line) is reduced significantly, other lines would now be relatively hotter, as then by the Laws of Thermodynamics there would be a transfer of heat from untreated lines to the now cooler line. Therefore, as a result of the interdependencies of one line with the others, after the completion of the preceding hottest line, a decision on the treatment sequence of the other lines would require identifying the next hottest remaining line!

In conclusion, a metro that has no surface lines would not benefit from having its trains painted with solar reflective paint or being fitted with low emissivity glass windows, provided stabled trains are properly managed. Conversely, metros with a mix of surface and sub-surface lines and indeed overground trains would benefit greatly from having their rolling stock painted with solar reflective paint and windows fitted with highly reflective glass.

Furthermore, in an era of heightened and pressing environmental concern, the application of solar reflective paint and the incorporation of highly reflective glass windows are very cost-effective, particularly when compared to the capital cost of installing mechanical cooling solutions, and longer term will deliver real on-going reductions in maintenance and energy running costs.

A final thought! Of all the mitigation works ever implemented under the Cooling the Tube Project, the limited solar reflective foil and film treatment of Central Line trains, reducing the internal temperature of the saloons by some 40C, has proved by far the most successful. If my information is correct, and I believe it is, the Green Park Station Ground Source Cooling Project was tendered at around £12M and the final costs was more like £25M …… and it would have made little or no difference to train temperatures.

For that sort of money, you can buy and apply an awful lot of high-performance solar reflective paint and install a lot of Low-E glass windows.

On reflection – absolutely pun intended – the solar reflective paint and Low-E glass windows will reduce the amount of heat absorbed by trains travelling on the surface in the summer, because the trains will be able to jettison this heat continually along the overground route BEFORE THEY REACH AND ENTER THE TUNNEL.

“I wish we were on the right track!” Think Sun Cream for trains!

 

Author: Calvin R Barrows, BSc (Hons), CEng, MICE

Cooling the Tube – on Ice till 2030?

Cooling the Tube – on Ice till 2030?

Author: Calvin R Barrows, BSc (Hons), CEng, MICE

 

Hang onto your handrail, if it’s not too hot, fellow tube users, I am just about to share my controversial theory about Cooling the Tube, which has resulted in some folk getting rather hot under the collar.

Please stay aboard, because for the Cooling the Tube Project ever to be successful, there are fundamental points at issue that still need to be considered and resolved. I am hoping that summarising my findings and research to date along with my interpretation of these, will initiate some serious and constructive debate among engineers, scientists and anyone with an interest in this matter.

In this article, I shall:

  • consider the extent of the problem, and how it affects passengers;
  • set out the circumstances that led me down this very different route;
  • identify the probable causes of the over-heating, based on my direct experiences,observations and temperature measurements;
  •  discover how another underground network, conceptually similar, albeit with some
    subtle differences, fares with overheating; and
  •  suggest possible solutions specifically for the configuration of London Underground’s
    infrastructure.

Finally – for the reader – there is an enlightening question to be considered!

A well-defined problem is half solved – paraphrased from Charles Kettering.

 

First, the very title of the project “Cooling the Tube” is a misnomer. Consequently, the search for a solution to the problem has been misled. The challenge is not simply “Cooling the Tube” or even “Cooling the Underground Network”: to be precise I would define it as “Cooling the Whole LU Network in the Summer”, since both overground and underground overheat in the summer!

Secondly, having spent years commuting on the Central Line and monitoring the seasonal temperatures differences at various times of day, I came to the irrefutable conclusion that the trains were gaining more heat overground than underground in the summer.

Let’s dispel the myth circulating that the Tube is hot all the year round, because in the winter passengers wear their thick coats and scarves while standing or sitting comfortably inside an electrically heated carriage. Conversely in the summer, passengers wear light clothing – yet are still frequently getting close to heat exhaustion during heatwaves and the hotter weather generally.

The project’s stated objective is two-fold – comfort and safety. For comfort cool trains are the priority, since passengers may spend 5-10 minutes on a platform but perhaps 45 minutes to an hour on a train.

For safety we need cool trains and cool tunnels, the cool tunnels being key to maintaining cool trains when underground. If passengers were trapped for some considerable time in an overheated, stalled train, within an
overheated tunnel, the outcomes for them could be very grave. So, the decision to expend all that effort and money cooling underground stations was erroneous, and indeed has been a wasteful diversion from addressing the real problem – because passengers are free to leave a station, for a place of safety, if they are overheating there!

Heat Sources

Many alternative reasons for the overheating in the summer have been proffered – including the combined effect of the tunnel, train and station systems; traction; braking; mechanical losses; passengers; the heat accumulating in the London clay; and so on.

All these are red herrings – either because they do not change significantly throughout the year, so they don’t explain the seasonal variations, or in the case of the London clay temperature, it’s not a cause – it’s an effect. The key issue
is that many of the tube trains run both over- and underground.

These are inevitably going to be affected by the overground, ambient temperature and solar heat gain. So rather than “the primary heating of the carriages happens in the tunnels”, my assertion is that “the primary heating of the carriages does not happen in the tunnels”.

My initial, subjective observation struck me as odd in that, travelling overground towards Epping during a late summer afternoon with progressively less passengers on board, the carriage seemed to become markedly hotter. My subsequent temperature monitoring clearly confirmed that up to a 6°C increase in temperature was not uncommon in the summer between Leyton and Epping.

The only logical conclusion was that the train was being heated by the surrounding hot, ambient air and “superheated” by solar irradiation (heat gain from the sun).

However, what, if anything, could that have to do with the over-heating in the tunnels? When travelling overground, the sun not only heats the inside of carriages directly, but the solar irradiation is also absorbed by the external skin of the train.

If a child’s slide can get so hot in the sun as to cause them serious burns; if tarmac roads can melt; if a car can become too hot to touch; and if untreated train tracks can reach 20°C above ambient temperature and buckle – then by the same token train bodies can absorb heat from the sun on their external surfaces and then emit some of that “super-heat”.

These overheated “storage radiators” will constantly emit this absorbed heat until they reach a state of equilibrium. However, being continuously heated by the sun, they cannot reach a state of equilibrium before entering the tunnel, so they continue emitting heat into the tunnel. Clearly then overheating is a network problem – the Laws of Thermodynamics can’t have it any other way!

Although the level of heat emission is unharmful on the surface, when these 200 tonnes of train enter the tunnel, with a thermal capacity estimated at 100-200 MJoules/°C, they continue to emit heat to detrimental effect. If all that were not enough, every time these trains enter the portals in the summer, they are also pushing/dragging in a plug of hot, ambient air, adding to the heat load in the underground network.

The yearly cycle from Autumn 2017 has seen ambient overground temperatures vary from -5°C to +35°C. This 40°C temperature difference of the air introduced into the tunnels by the piston and drag effects undeniably makes a significant difference to the tunnel temperatures between summer and winter.

When comparing the London network with that of Glasgow, similar in concept but ALL underground and with shallower tunnels at a depth of ≈ 9 metres (30 feet), their tunnel ambient temperature hovers around 16°C all year-round, even during their 31°C heatwave of the summer of 2018. Because it is wholly underground, it suffers neither from solar irradiation nor the portal piston/drag effect.

Additionally, unlike most of the London Underground rolling stock, Glasgow’s trains are stabled appropriately during the heat of the day, in roofed train sheds with the doors open – parasol effect!

Mitigating the factors causing this specific overheating problem on London Underground’s network really does not need to be difficult but does require an uncommon solution. Whilst many national overground trains are already being successfully air-conditioned, with trains underground the waste heat would be expelled into the overheated tunnels, leading to probable equipment failure.

Moreover, any cooled air in the trains would soon be overwhelmed by this overheated tunnel air. Therefore, installing or retro-fitting air-conditioning to the entire London Underground train stock, even if feasible, would be wholly unrealistic and ineffective.

However, to deal with solar irradiation there is no sensible reason why trains that run both over- and underground should not be coated with a high-performance, solar-reflective paint and be fitted with high-performance, solar-reflective glass windows. Equally, trains should be appropriately stabled in the non-peak times – some depot buildings may not be very suitable, if they are likely to be affected by solar heat gain themselves. It might be better to provide well ventilated shading, built with a finned roof and walls (Venetian blind form) and with the openings facing north – parasol effect again.

Additionally, limiting the transfer of ambient summer air into the underground network should be addressed – indeed The Rail Safety and Standards Board (RSSB) recommends this be considered! On sub-surface lines the piston/drag effect is less marked because of the configuration of the portal openings, the more frequent “cross-passages” between the two tracks and the less restricted, overline ventilation shafts and openings. For the deep lines it’s a different story.

Their portals will probably need some remodelling; perhaps incorporating some form of cooling, diversion or dispersal of the ambient summer air – or a combination of all three.

Clearly, there is a need for appropriate and detailed train temperature monitoring throughout an entire year, to agree upon the real causes of summer overheat – and dispel the myths. Evidently TfL has not undertaken such formal monitoring to date, since they still mistakenly claim that “the primary heating of the carriages happens in the tunnels”.

In summary, whilst not confusing causes with effects, we need to be very clear about both the problem, and the root causes, the removal of which will resolve or dramatically reduce that problem.
Therefore, with an over- and underground network such as London Underground’s, this demonstrates the key factors causing overheating are trains travelling on the OVERGROUND sections of the network combined with the summer weather.

Finally, a quote from the Vienna Metro in their e-mail to me – “We appreciate your interest. As a
matter of fact, the sun is the main cause for the overheating problem for the U6 [be]cause of the long
overground route”.

 

Author: Calvin R Barrows, BSc (Hons), CEng, MICE

Top 10 Fastest Trains in the World

Traveling Europe by train is already faster than by plane right now, and Japan is testing a “Supreme” version of its popular high-speed trains, set for a 2020 debut ahead of the next Winter Olympics. You can’t ride that one just yet, but there are more than a few bullet trains available to speed up your travels. Here are the world’s fastest high-speed trains in commercial service, ranked by speed:

1. Shanghai Maglev: 267 mph

The world’s fastest train isn’t the newest, the shiniest, or even the one with the most expensive tickets. Charging $8 per person, per ride, the Maglev runs the nearly 19 miles from Shanghai’s Pudong International Airport to the Longyang metro station on the outskirts of Shanghai. That’s right—the train, which takes just over 7 minutes to complete the journey using magnetic levitation (maglev) technology, doesn’t go to the city center. As such, the bulk of the passengers since its 2004 debut have been travelers on their way to and from the airport, cameras out and ready to snap a photo of the speed indicators when the train hits 431 km/hr (267 mph).

2. Fuxing Hao CR400AF/BF: 249 mph

China wins again, also serving as home to the world’s fastest non-maglev train currently in service. The name “Fuxing Hao” translates to mean “rejuvenation,” and each of the two trains have been branded with nicknames: CR400AF is “Dolphin Blue,” and the CR400BF is “Golden Phoenix.” The “CR” stands for China Railway. Both take just under five hours to zip up to 556 passengers each between Beijing South and Shanghai Hongqiao Station, easily halving the nearly 10-hour time it takes to ride the conventional, parallel rail line between these two megalopolises. The “Rejuvenation” also beats China’s next fastest train, the “Harmony” CRH380A; it has dazzled since 2010, with speeds of up to 236 mph on routes connecting Shanghai with Nanjing and Hangzhou, and Wuhan with Guangzhou.

3. Shinkansen H5 and E5: 224 mph

Japan is celebrating the 54th anniversary of high-speed train travel this year, since it was way back in 1964 that the Hikari high-speed train launched service between Tokyo and Osaka, cutting travel time between the country’s two largest cities from nearly seven hours to a mere four by rail. The H5 and E5 series Shinkansen, respectively running the Tohoku and Hokkaido services, are two of the newer bullet trains on Japan’s tracks, and so far the fastest in regular commercial service in the country.

4. The Italo and Frecciarossa: 220 mph

Italy’s dueling train operators, NTV and Trenitalia, each flaunt a high-speed train that tie as Europe’s fastest, capable of shuttling passengers from Milan to Florence or Rome in under three hours, with a new route to Perugia debuting this year. The Frecciarossa, or “red arrow,” was unveiled during Expo 2015, held in Milan, and the train is remarkable as much for its speed as for its construction; its components are nearly 100 percent renewable and sustainable.

5. Renfe AVE: 217 mph

Spain’s fastest train is the Velaro E by Siemens, and it is used for long-distance services to major Spanish cities and beyond: traveling from Barcelona to Paris can now be accomplished on high-speed rail in six hours.

The DeutscheBahn ICE reaches speeds of 205 mph.Courtesy Deutsche Ban

6. Haramain Western Railway: 217 mph

The Mecca-Medina high-speed link stretches the 281 miles between Saudi Arabia’s most holy cities and has been in partial operation since December 2017, with full completion set for early summer 2018. Traveling the length of the route takes two and a half hours, compared to five hours by car. Speed isn’t the entire justification for the construction of this railway, however; the Haramain is expected to carry three million passengers a year, including many Hajj and Umrah pilgrims, relieving traffic congestion.

7. DeutscheBahn ICE: 205 mph

The distinctively futuristic white and silver of the Inter-City Express, or ICE, combined with its sharp red cheatline, makes an impressive sight speeding through scenic German countryside, especially on its newest route connecting Berlin and Munich. Similar to Spain’s Renfe AVE train, Germany’s fastest train is another Siemens design, the Velaro, and was built to fit through the Channel Tunnel. That’s a serious asset for DeutscheBahn’s long-term plans to operate these trains from Frankfurt to London.

8. Korail KTX: 205 mph

South Korea’s high-speed rail network is far from the newest (the KTX debuted in 2004), but it does hold its rank among the fastest. The latest route, opened just in time for the 2018 Winter Olympics, connects Incheon International Airport in the west to the coastal town of Gangneung in the east, stopping in Seoul along the way. The KTX cuts the transport time to reach the ski slopes of PyeongChang from six hours by conventional train to under two hours.

9. Eurostar e320 and TGV: 200 mph

Both the TGV and Eurostar e320 trains are tied for next on the list, but the latter underwent a redesign in 2015. Named for its top speed of 320 km/hr (200 mph), the e320 series is the first tip-to-tail redesign of a Eurostar train in the company’s 22-year history. The speedier trains—20 km/hr faster than the earlier, e300 series—are capable of trimming another 15 minutes off the already zippy Eurostar trips of around two hours between Brussels, Paris, and London (and Amsterdam, later this year). Since Eurostar delivers its passengers right to the center of each city and fares are available with Rail Europe from $70 one-way, it’s a wonder anyone still flies between the cities.

10. Thalys: 186 mph

Connecting Amsterdam, Brussels, Paris, and Cologne with multiple daily services, the Thalys is one of Europe’s most important train lines for both leisure and business travelers; in fact, its ridership is almost an even split between the two categories. In December 2015 the German route was extended as far as Dortmund, though the Brussels-to-Paris run remains critical, making up more than half the business.

The Benefits of Understanding your Track Geometry Measurements

The Goal

The overall goal of track maintenance is to deliver the track, to support the timetable. This is achieved by Rail and Transit owner-operators through four objectives. First, to deliver safety to all passengers and staff, safety for passengers who depend on the rail system. Second, to deliver a reliable rail system, to ensure that the required services are available and that all assets are fit for purpose. Third, to deliver economic prosperity for a rail organization, through optimal and sustainable maintenance activities; and lastly, to deliver a comfortable ride for the consumer, reducing noise and improving ride quality. To deliver these goals, a rail organization must understand the criticality of all their assets, and the condition, along with the quality of the track they own and operate on.

Linear Measurements

Track Geometry measurements are a key component to understanding if the track is fit for purpose and is in a state of good repair. Periodic track condition measurements are required to evaluate the track quality and maintain an effective railway track system. Today most railroads already collect track geometry measurements from recording vehicles; however, often rail operators are not utilizing the data to its full advantage and sometimes data sets are held in siloed systems; making it almost impossible to visualize different condition data at the same time. Track Geometry contains a wealth of information that can support a range of maintenance and renewal decision support.

Core Track Geometry Measurements and Calculations

Gauge; the distance between the running edge of the left and right rail. There are several gauges used globally, the standard gauge is 1,435 mm (4 ft 8 1⁄2 in) and is typically used in North America and most of Europe. As the linear asset degrades, the distance between the rails will increase. This deterioration can cause a train to derail.

Curvature; one way to survey a track alignment is to measure the offsets from a chord to the running edge of the rail at the centres of successive overlapping chords, laid out along the outer rail of the surveyed track, this offset is called a versine.

Superelevation; is a difference in height between the left and right rails. It is generally applied in curves, with the low rail being on the inside edge of the curve. It is applied to offset the lateral forces that are felt when a vehicle traverses a curve.

Vertical Track Variation; a challenge for some individuals to understand is that the underlying geometry is not important; for example, a hill or a valley was already designed into the system. However, if there is a bump or a dip in the track on a hill, that is the information that is needed for extraction. The hill is viewed as a zero, we want to pay attention to the oscillations or variations in the track geometry data. As a general rule, if it takes less than two seconds to go through the variation at line speed, then we consider the variation; and if it takes more than two seconds, then we don’t consider the variation.

Lateral Track Variation; horizontal track geometry is generally filtered in the same way as vertical track geometry. We are looking for features that can be traversed in less than two seconds at line speed. The two seconds is derived from ISO 2632 – Human Comfort.

Track Twist; the difference in cross-level between two points or the rate of change of superelevation and measured over the impact on the bogie; this should be calculated based on the smallest wheelbase used by the owner-operator. A worst-case scenario is that the front wheel would drop onto a twist causing the rear wheel to climb, resulting in a train derailment.

Core Channels from a Track Geometry System

Location; beyond recording what the track geometry is, the system needs to record where it is as well. This is often one of the main issues with geometry data, as the same feature can be recorded at slightly different locations on different recording runs. Distance measured along the track can be derived from a tachometer fitted to one of the axles. This is a reasonably effective mechanism, but errors can be introduced as the wheel wears and if the recording vehicle runs around curves at different speeds. This can be corrected by GPS where available, or by detecting known features along the network and marking them against the recording. Lastly, the location should be reported against the linear referencing system (LRS) for the track, not against the distance traveled by the recording vehicle.

Speed; the FRA defines the maximum allowable posted timetable operating speed using the Vmax formula. We can take our curve data and plot the max speeds on our track charts. Additionally, we can calculate the equilibrium speed, which is the minimum speed that should be traveled through a curve. If locomotive traverses through the curve above Vmax speed, this causes extra wear on the outside rail; and if the locomotive traverses through the curve below the equilibrium speed, then this causes extra wear on the inside rail. This can be tracked and shown in our track charts with real locomotive speed data, to ensure operators are traversing through curves at the appropriate speed.

By Robert Henderson – Rail and Transit Consultant at Bentley Systems

Why does it cost between $25-$39 million to construct a kilometer of high speed rail in the European Union?

Why does it cost between $25-$39 million to construct a kilometer of high speed rail in the European Union?

 

This $25–39 million per km figure appears to be derived from a 2014 World Bank report that compared the construction cost of Chinese high-speed rail (HSR) projects to comparable European ones. In the same report, Chinese HSR costs ranged from $17–21 million per km, or roughly 30–50% less expensive.

The best way to understand where these numbers are coming from is to dig into the major cost elements of your typical high-speed rail project. Here is a table from that report that looks at the cost breakdown of typical Chinese HSR projects at various speeds:

Source: World Bank — High-Speed Railways in China: A Look at Construction Costs (Page 4)

We will go through each of the categories above to explain how and where the cost differences may be coming from:

  • Land acquisition and resettlement — HSR lines need to be pretty straight to accommodate high-velocity rolling stock and land usage rights along this path need to be acquired. Since property rights are weaker / less developed in China, it is fairly straightforward and thus relatively inexpensive to acquire these land usage rights. This also often involves displacement of existing populations and in China project planners factor in resettlement costs — mainly in the form of building new housing for displaced farming families.
  • Civil works — As one can imagine, there is a ton of civil engineering and construction involved in high-speed rail projects. Unlike regular rail, high-speed rail lines need to be straight. To achieve this, you are often forced to build lots of raised viaducts or bore tunnels in hilly/mountainous areas. This was the biggest area of cost for Chinese HSR projects, a combination of (mostly) labor and raw materials (e.g. cement, steel, gravel, stones etc.).
  • Track — Self-explanatory.
  • Signaling and communications — Specialized systems to manage the entire system and make sure trains don’t crash into each other. Lots of signaling equipment, network equipment, fiber optic lines and software.
  • Electrification — HSR trains are electric and draw power from the electrified track.
  • Rolling stock — The high-speed trains themselves.
  • Buildings including stations — Train stations and related intermodal links (e.g. local metro, bus station, taxi and airport).
  • Other costs — Sometimes (but not always) capitalized interest is included in the total project cost.

 

 

The main reasons why European projects were more expensive most likely boiled down to a few key factors:

  • Higher labor costs — Labor is the largest cost item in civil works and track-laying. European labor is several times more expensive than Chinese labor.
  • Higher land acquisition costs — Stronger property rights in European Union countries means that project planners need to shell out more cash to acquire land along the line’s path. Paying more for the land is not necessarily a terrible outcome, as it represents an internal transfer of wealth from the public to landowners along the track’s path hoot necessarily good either). However, the bigger issue here are delays that it may cause in the construction phase if certain holdouts — leveraging their property rights — refuse to acquiesce (better eminent domain law/process can alleviate this). Longer construction periods translate into higher build and financing costs. To illustrate this point: The Chinese HSR projects usually took 3 to 4 years to complete once construction began while European projects took 2 to 3 years longer.
  • Differences in economies of scale — The sheer scale of Chinese HSR allowed for significant standardization in process, technology, materiasl procurement and design. For example, raised viaducts were preferred in China to “minimize resettlement and the use of fertile land as well as to reduce environmental impacts” (page 5, World Bank Report). Following this, there were a massive number of viaducts that needed to fabricated and attached. So each section was built to standardized specifications (24 or 32 meters, weighing between 750 and 800 tons) and special machinery was invented to lay the viaduct quickly and efficiently.

 

There were differences in other categories as well, but much smaller in impact:

  • Train stations — One thing you will notice about most new Chinese train stations (exception being “mega” stations in Tier I transportation hub cities like Beijing or Wuhan) is that they look quite similar in layout and design. This was done on purpose. Since they were building so many train stations at the same time, many of the designs were standardized from station to station which saved cost. Meanwhile you will notice that many of the European stations are quite unique in design. Basically, Europeans paid more for aesthetics, which while subjective is not necessarily a bad thing either.
  • More expensive rolling stock — France (Alstom), Germany (Siemens) and China (CRRC) used mainly domestically manufactured trains for their networks. Chinese trains are less expensive, reflecting lower embedded labor costs as well as greater economies of scale in manufacturing.
  • Raw materials — Another embedded cost item is materials cost (cement, steel and other raw materials), but since these are commodities, I do not think the cost difference would be that significant.

It is also possible that there were differences in terrain that increased the civil engineering requirements (e.g. bridges and tunnels), but you could really only assess this by looking at the detailed topography on an individual line basis.

Railway Sleepers – Types of Sleepers

Railway Sleepers – Types of Sleepers

 

Depending upon the position in a railway track, railway sleepers may be classified as:

  1. Longitudinal Sleepers
  2. Transverse Sleepers

1. Longitudinal Sleepers

These are the early form of sleepers which are not commonly used nowadays. It consists of slabs of stones or pieces of woods placed parallel to and underneath the rails. To maintain correct gauge of the track, cross pieces are provided at regular intervals.

At present this type of sleepers are discarded mainly because of the following reasons.

  • Running of the train is not smooth when this type of sleepers is used.
  • Noise created by the track is considerable.
  • Cost is high.

2. Transverse Sleepers

Transverse sleepers introduced in 1835 and since then they are universally used. They remove the drawbacks of longitudinal sleepers i.e. the transverse sleepers are economical, silent in operation and running of the train over these sleepers is smooth. Depending upon the material, the transverse sleepers may be classified as:

  • Timber/wooden sleepers
  • Steel sleepers
  • Cast Iron Sleepers
  • Concrete Sleepers

Timber or Wooden Sleepers

The timber sleepers nearly fulfilled all the requirements of ideal sleepers and hence they are universally used. The wood used may be like teak, sal etc or it may be coniferous like pine.

The salient features of timber/wooden sleepers with advantages and disadvantages.

Advantages of Timber Sleepers

  1. They are much useful for heavy loads and high speeds
  2. They have long life of 10-12 years depending upon the climate, condition, rain, intensity, nature of traffic, quality of wood etc
  3. Good insulators and hence good for track circuited railway tracks
  4. They are able to accommodate any gauge
  5. Suitable for salty regions and coastal areas
  6. Can be used with any section of rail
  7. Can be handled and placed easily
  8. They are not badly damaged in case of derailment
  9. They are not corroded
  10. Cheaper than any other types of sleepers

Disadvantages of Timber Sleepers

  1. Liable to be attacked by vermin so, they must be properly treated before use
  2. Liable to catch fire
  3. They do not resist creep
  4. They are affected by dry and wet rot
  5. Become expensive day by day
  6. Life is shorter compare to others

Steel sleepers

They are in the form of steel trough inverted on which rails are fixed directly by keys or nuts and bolts and used along sufficient length of tracks.

Advantages of Steel Sleepers

  1. Have a useful life of 20-25 years.
  2. Free from decay and are not attacked by vermins
  3. Connection between rail and sleeper is stronger
  4. Connection between rail and sleeper is simple
  5. More attention is not required after laying
  6. Having better lateral rigidity
  7. Good scrap value
  8. Suitable for high speeds and load
  9. Easy to handle
  10. Good resistance against creep

Disadvantages of Steel sleepers

  1. Liable to corrosion by moisture and should not because in salty regions
  2. Good insulators and hence cannot be used in track circuited regions
  3. Cannot be used for all sections of rails and gauges
  4. Should not be laid with any other types of ballast except store
  5. Very costly
  6. Can badly damaged under derailments
  7. Way gauge is obtained if the keys are over driven
  8. The rail seat is weaker
  9. Having good shock absorber as there is not cushion between rail foot and ballast

Cast Iron Sleepers

They consist of two pots or plates with rib and connected by wrought iron tie bar of section of about 2″ ½”    each pot or plate is placed below each rail.  The pot is oval in shape with larger diameter 2′-0″ and smaller diameter 1′-8″ is preferred. Plate sleepers consist of rectangular plates of size about 2′ – 10′ x 1′ – 0″.

The relative advantages and disadvantages are given below.

Advantages of Cast Iron Sleepers

  1. Long life upto 50-60 years
  2. High scrape value as they can be remolded
  3. Can be manufactured locally
  4. Provided sufficient bearing area
  5. Much stronger at the rail seat
  6. Prevent and check creep of rail
  7. They are not attacked by vermin

Disadvantages Cast Iron Sleepers

  1. They are prone to corrosion and cannot be used in salty formations and coastal areas
  2. Not suitable for track circuited portions of railways
  3. Can badly damage under derailment
  4. Difficult to maintain the gauge as the two pots are independent
  5. Require a large number of fastening materials
  6. Difficult to handle and may be easily damaged
  7. Lack of good shock absorber
  8. They are expensive

Concrete sleepers

R.C.C and pre-stressed concrete sleepers are now replacing all other types of sleepers except to some special circumstances such as crossing bridges etc here timber sleepers are used. They were first of all used in France round about in 1914 but are common since 1950. They may be a twin block sleepers joined by an angle iron. It may be a single block pre-stressed type.

Advantages Concrete Sleeprs

  1. Durable with life range from 40-50 years
  2. They can be produced on large quantities locally by installing a plant
  3. Heavier than all other types thus giving better lateral stability to the track
  4. Good insulators and thus suitable for use in track circuited lines
  5. Efficient in controlling creep
  6. They are not attacked by corrosion
  7. Free from attacks of vermin and decay, suitable for all types of soils
  8. Most suitable for welded tracks
  9. Prevent buckling more efficiently
  10. Initial cost is high but proves to be economical in long run
  11. Effectively and strongly hold the track to gauge
  12. Inflammable and fire resistant

Disadvantages Concrete Sleepers

  1. Difficult to be handled
  2. Difficult to be manufactured in different sizes thus cannot be used in bridges and crossing
  3. Can be damaged easily while loading and unloading
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