Questions tagged [rail]

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What is the purpose of this dead-end rail junction?

This rail junction is located on a steep, short, local railroad line from the "mainline" in Reno, NV to the community of Stead. The track is new/maintained and there is no evidence of an old siding. ...
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0answers
22 views

Do high speed trains use ventilation and filtration systems similar to aircraft?

This article discusses the ventilation and filtration in aircraft: Ventilation rates provide a total change of air 20 to 30 times per hour. Most modern aircraft have recirculation systems, which ...
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1answer
35 views

Why would a specfication for a motor require that overtemperature protection be realized by modeling heat generation and not with an embedded sensor?

I'm reading the procurement documents for the R211 railcar contract, which is for electric multiple unit subway cars designed for rapid transit applications in New York City. The railcar's propulsion ...
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1answer
33 views

Why are tank cars cylindrical?

Hold height constant. Then a Rectangular Prism, with length and width = radius of the cylinder, has greater volume! So why aren't tank wagons (railroad vehicles that transport gas and liquid) ...
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1answer
51 views

Why do trains use the same wheels for staying on track and propulsion?

Trains where originally designed to keep the train on track. At the time trains where pulled by horses and used to transport coal (and such) out of mines. The two functions have very different ...
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1answer
51 views

How does dynamic braking work with railway locomotives?

General Electrics boasts that its Evolution series diesel-electric locomotives are capable of dynamic braking. Dynamic braking uses the electrical traction motors on the locomotive axles - motors are ...
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6answers
7k views

What is the purpose of these “partially filled in” locomotive wheels?

I recently visited a railway museum with a lot of Soviet-era locomotives. The picture below shows the wheels on a locomotive from the 1930s or 1940s. Some of the wheels are thicker on one side (as it ...
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7answers
11k views

What are the engineering principles for a train to get electricity from the railway

How many general methods are there for transferring electricity from the railway to a train? I could see that some trains are connected by a pantograph and some have a third rail. Are there any ...
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1answer
154 views

What are these reflective triangles on the sides of train track rails for?

Last night while waiting for the train at South Yarra station in Melbourne, I saw these reflective triangles stuck on the sides of the train track rails. They were evenly spaced a few metres apart for ...
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2answers
125 views

Is there any reason why “inner-flange” style trains are almost universal?

There's basically two ways train wheels can operate, the flanges could be either "inner" or "outer". Switches can be made in equivalent ways for inner and outer flanges. We could expect that, just ...
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2answers
78 views

How do maglev trains turn given that they seem to have more than two bogies per car?

All of the images of maglev trains that I've seen seem to have a continuous drive mechanism along the entire length of each car: I assume this must be articulated some how, or the train wouldn't be ...
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0answers
62 views

What does “'LBLMY” mean on the side of a railcar?

In this photo, what does 'LBLMY signify? Seeing it directly under the capacity, and 5000 pounds lower, I'm guessing it's a "limited capacity" of some sort. But I ...
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1answer
97 views

Can a Foucault's current brake be used on the rails themselves to brake trains?

Your typical Foucault's current brakes operate on a disk, which is placed in an electromagnetic field in order to transform kinetic energy into heat without friction. The problem is that the disk ...
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1answer
94 views

What's this box in steam locomotives?

In the past few weeks I've seen several European steam locomotives in museums. I noticed several of them have a box in the driver's cabin, similar to the one in the picture I've attached. Several ...
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1answer
126 views

What are the factors that made narrow-gauge railways cheaper in the early 1900s, and are they still applicable today?

Back when railways were being massively build, in the 1900-1910 decade for example, most new lines were made with narrow gauge, instead of the standard gauge which is 1435mm for most of the world. ...
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0answers
59 views

Is there a particular reason the Moléson funicular is built as a giant bridge?

So I live in Switzerland and there is lots of funiculars in my country. Most of those were built between 1890 and 1930, and for most of those the line is on the ground most of the time, there is ...
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3answers
2k views

How do gapless rails deal with thermal expansion?

Gapless railroads have their joints welded together to reduce noise. The lack of a gap between rail sections also reduces wear on both the track and the wheels. However, because the weld essentially ...
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3answers
436 views

What determines the maximum possible slope of rail transportation (without rack)?

(Disclaimer: To make things clear I'm talking about adhesion railways and excluding rack railways as those are an entirely different technology and requires specially equipped vehicles. Also I'm ...
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0answers
32 views

Specific Questions about Traffic Signal Preemption at Grade Crossings

Several questions, regarding traffic signal preemption at a grade crossing Is the preempt relay, which triggers the preemption sequence, located inside the bungalow which houses the grade crossing ...
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0answers
98 views

How to define the Clothoid Constant in Clothodial Arc ( Spiral Curve)?

Referring to the document here on IfcClothoidalArcSegment2D, we have ClothoidConstant, which is defined as The constant $A$ (not $A^2$), that determines the ...
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2answers
102 views

Sudden increase in noise levels - subway noise -happend overnight [closed]

This is real life issue I am having currently and I am puzzled as to why it happened. I have lived over the subway lines (two actually each going in the opposite direction, two sets of tracks) for ...
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0answers
92 views

Cone shaped train wheels

I was watching this Feynman video and (as usual) his explanations make a lot of sense. Now I just took a train, and am not so sure anymore. Looking at the train wheels they did not appear cone ...
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1answer
52 views

Why is there a delay with railroad signals? [closed]

Ok so. When you look in videos(or in real life) with the railroad signals, when a train passes over it, it takes around 3 to 5 seconds for it to actually change to the correct aspect. What is up with ...
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4answers
347 views

Why do trains not have a high-friction emergency braking system?

Looking at the capacity of train networks, systems like CBTC help increase capacity, but the spacing of trains is ultimately limited by poor braking performance. In my understanding, safe distances ...
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1answer
51 views

Mechanical Engineering- Modeling contact in Abaqus

I have simulated a 2D model in Abaqus which indicates 2 main part, first a sector that represent as wheel and, second a rectangular that represent rail. the wheel and rail are in contact and wheel ...
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1answer
151 views

How can traffic signal controllers handle multiple conflicting preemption requests of equal priority without dropping one?

Let us assume that we are North American traffic engineers, and have the (hypothetical, plausible, yet pathological) intersection configuration depicted (not to scale and lacking lane lines, sorry -- ...
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1answer
240 views

Monorails - why even have them?

My (highly limited) engineering intuition says: Dual railing is good - for balance, for switching of tracks, for lightening load and making sure it is applied in basically the same direction always, ...
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7answers
6k views

Why do electric trains arc at high speeds?

When I watch videos of high speed trains I always see explosions of electricity near the top, or arcing. Why does that happen? I know that the Acela does it a lot but other high speed trains have it, ...
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1answer
135 views

Balancing Locomotive Power

My first post here. I'm curious about how power is balanced in multiple diesel-electric locomotives. I understand to that two locos can be ganged in terms of controls, to set speed etc, so that one ...
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3answers
602 views

Why do train cars have unevenly spaced axles?

Every train car I can remember has its axles arranged like the photo. Two are put very close together in one chassey, and two more the same way at the other end. But why do that? If you want 4 axles, ...
3
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1answer
111 views

Why are rail signals overbuilt compared to road signals?

Here is a photo of a railroad crossing near a road intersection. Traffic, Rail Lights out of Sync at Fruitvale Avenue Crossing The road signals are mounted to slender poles (or even suspended from a ...
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1answer
87 views

What is this indicator called?

None of my fellow commuters know what this white panel with, what appears to be a red slider attached, is called and what it is for. This particular one is on a platform edge which happens to be over ...
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1answer
108 views

Does the decrease in speed of the train at the curvature changes the properties of Speed Time Curve Of Urban Service

Ok, I wish to plot the speed time curve of the my urban service . The travel includes the curvature ( as shown in image ( just for reference )). The train speed is decreased while it runs along the ...
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2answers
2k views

Why do some high speed trains have long noses, while others do not?

Why do some high speed trains like the Shinkansen E5 and E6, have really long noses while other trains, like the Eurostar and Javelin, have shorter noses? How does the shape of the nose affect the ...
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2answers
718 views

Why use rectifier / inverter in locomotives?

Image Source Why not just take the AC from the alternator to the motors? Why go AC to DC to AC again?
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2answers
1k views

For train track, why does the ballast need “good drainage”?

Why does the ballast of train track need good drainage? I read something about preventing "fouling" of the ballast, but don't know what that means or why it would be structurally bad. Could ...
3
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1answer
390 views

Why do all high-speed trains run on electric track (as opposed to normal track with diesel-electric trains)?

AFAIK, all high speed trains (200+ kmh) run on electric track. Why is this? Is there something about a diesel-electric engine that makes high-speed trains more difficult? Here's some other data, and ...
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3answers
351 views

Two railway locomotives connected one after another

I am relatively new (not in terms of registration but in terms of activity) on this site. I don't know if this question is suited here. I have seen two rail locomotives connected one after another ...
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2answers
421 views

Train Signalling - What Do They Mean

I'm asking this here because I really cannot find a better place to ask this. Near my house (in the US), there is a pair of parallel train tracks operated by Union Pacific, primarily for cargo-...
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2answers
123 views

Historically, how did tram switches work?

Historically, the switches on regular railways were switched manually using a lever by dedicated staff to route trains correctly before getting replaced by an automatic electronic system. A similar ...
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7answers
8k views

Why would a train automatically derail if a signal is passed at danger?

In a recent incident in London Network Rail said an empty train had travelled past a red signal, which resulted in an automatic derailment. No one was injured. [link] The derailment has caused ...
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2answers
235 views

How to notate the position of a train?

How is the position of a train modeled in a computer control system? I can think of two basic approaches but I am not sure which (if any) are used in the real world. Lat, Long Ex: (-42, 23) The ...
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2answers
305 views

On a Diesel/hydraulic DMU train what exactly does the “go faster” lever control?

Let's say that you are driving a Diesel Multiple Unit† with either mechanical* (i.e. an actual gearbox with multiple ratios) or hydraulic (i.e. two or more torque converters) transmission. When you ...
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1answer
9k views

How do train tracks handle really cold weather?

First of all, I'm interested in train track only, not the rolling stock. How are tracks built to cope with really cold weather? An example might be some place in Canada or Siberia. Ice would ...
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0answers
58 views

Could someone explain to me the process described in this quote from G.B. Shaw (fragile load transfer system of some sort)? [closed]

The idea, as I understand it, is to transfer fragile material (glass bulbs in this case, I believe) from one moving something to another, or over to a platform. This is taking place in the 1920's, I ...
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1answer
1k views

Why does the Channel Tunnel enter the ground around 10 km from the coast?

I know that digging tunnels is always much more costly than building ways or train above ground. Why doesn't the Channel Tunnel start around the coastline? Why does it have an around 10 km long ...
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2answers
945 views

Is this railway carriage side likely made of single metal sheet?

A neat image from Wikipedia: Here the railway carriage side looks like it is crafted from a single sheet of metal (if we ignore the doors and the windows and some minor parts like that small thing ...
7
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1answer
295 views

What is required to implement Positive Train Control on railroads in the US?

Background On May 12, 2015, an Amtrak train derailed in Philadelphia, PA, killing 8 and injuring 200 people. I saw a story on the incident where multiple NTSB spokespeople have said at this and other ...
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1answer
4k views

How many train passes can railway tracks endure?

I know that the rubber on car and truck tires wear, and the road concrete wears out. I wondered: While steel is hard and elastic, it still causes friction (interaction between molecules) and ...
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4answers
3k views

If the emergency brake in a train is broken, do the passenger car brakes still work?

Scenario: Suppose the emergency brake button in the cab of a train is not working. Would the emergency brake cords / buttons in the passenger cars still work? This question is inspired by this ...