Questions tagged [rail]
Questions pertaining to railroads and railroad tracks
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Train disembarking: why don't trains allow exit at any point1890 v 2023
In the 1890s, trains allowed access/egress at every cabin in a car: this obviated the need for a hallway and saved space.
Why was this eliminated as early as the 1920s?
1890's style car:
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Can tyres placed on track derail trains?
This question is based on the following news article. I just want to know if rubber tyres are strong enough to cause rail derailment if placed on the track
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What is the difference between goods yard, goods station and marshalling yard?
In railway engineering what is the difference between goods yard, goods station and marshalling yard?
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Trains that do "never" have to stop
What are the limitations of trains that never stop. Can we have shuttles decelerating from the train's speed to 0km/h at the station for alighting passengers, while another shuttle picks up boarding ...
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Using lead screw with lead rod instead of two rods and lead screws
It is common setup to have two lead rods that carry a platform that needs to move on linear bearing. The platform itself is controlled by a separate lead screw connected to a stepper.
I'm looking for ...
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Why are multiple locomotives attached only to the front for larger trains?
For long freight trains and those that will be climbing to stations at higher altitudes, an extra or two locomotives are attached to the front. I've always wondered why.
For argument's sake, if there ...
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Why can't trains stop in 2x the distance of trucks from the same speed?
It is my understanding that every axle on a modern train has brakes.
According to this page https://www.engineeringtoolbox.com/friction-coefficients-d_778.html clean/dry steel on steel has a (static) ...
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Why are train brakes so complicated?
The concept is simple enough: no pressure in the train line has the brakes locked, full pressure is loose, and partial pressure drags accordingly. So if pressure is lost for any reason, the train ...
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How to calculate the deflection displacement of a circular looped, closed bending beam?
There is a given ring A, with a given cross section B. Ring A is placed on Columns C. The number of the columns is a variable, but minimum three.
The linear distance X between two columns can be ...
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Can you uncouple the locomotive from the rest of the train at high speed in an emergency? [closed]
I'm watching this movie, Final Run, in which a passenger train, traveling at high speed, loses control and becomes a runaway train. Some nonsense about some kind of new locomotive technology, and then ...
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How fast can the Shinkansen N700 train take a curve?
As a transit advocate, I'm evaluating an urban freeway corridor for high-speed rail. Given the geometry of the existing highway, the track alignment will be a compromise between train speed and right-...
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Why are railroad tank cars bent in the middle?
I recently noticed that the cylindrical shape of a railroad tank car is not completely straight but has a bend in the middle. The entire tank is a bit lower there. What's the reason for this bend?
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is this a picture of a plate girder train bridge or a deck truss train bridge?
Is this a picture of a plate girder train bridge or a deck truss train bridge?
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Why are trams always electrified with DC, while trains can be electrified either with AC or DC?
Trains can be electrified either with DC voltage or with AC voltage. Various networks across various countries uses various standards.
My question is however for trams, which are basically a lighter ...
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Could railway overhead wires be used for long distance electricity transmission?
Most electrified railway in Europe operates at 15 kV 16.7 Hz AC or 25 kV 50 Hz AC.
Power is typically produced between about 2.3 kV and 30 kV and stepped up to 115 kV to 765 kV AC for long distance ...
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Does westinghouse braking system prevent using anti-lock system?
This question concerns the Westinghouse braking system. If I understand correctly this video, in an emergency braking (e.g. in case of failure in main air pressure line) the pressure in the main ...
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Why railroad concrete tie tips become dry first after a rain?
I've witnessed this phenomenon:
Why are only the tie tips dry? Why are only the stones around the tips dry? This is a railroad in Ukraine in the morning after a rain at night. Around 80% of observed ...
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On the steam locomotives, why was the driver's cabin not located in the front of the boiler for better visibility?
I always wondered how the drivers of steam locomotives could observe the road.
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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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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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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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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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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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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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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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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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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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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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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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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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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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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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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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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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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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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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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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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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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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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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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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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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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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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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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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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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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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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, ...
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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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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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