Speed limits for freight trains

[DET63]

Given their length, freight train locomotives are often far from the caboose or EOT/FRED. When a train without a caboose is passing through an area with a low speed limit, can it start to speed up when it passes the point where the engine passes a point where a higher speed is allowed, or does the engineer have to estimate when the end of the train has passed the point where the higher speed limit is in effect?

I would think that, if the speed limit is in effect for a sharp turn, a bridge, or a similar hazard, that the last car would have to pass the danger point before it could speed up. OTOH, if the slow speed is for a blind crossing, then it would seem that once the engines passed it, the train could start to speed up, since anyone approaching the crossing would be able to see the train already moving through it.

Although I've put this in the miscellaneous discussion area, I would suppose it would also apply to Auto-Train, since it is rather long.

 

[Neil_M]

Given their length, freight train locomotives are often far from the caboose or EOT/FRED. When a train without a caboose is passing through an area with a low speed limit, can it start to speed up when it passes the point where the engine passes a point where a higher speed is allowed, or does the engineer have to estimate when the end of the train has passed the point where the higher speed limit is in effect?
I would think that, if the speed limit is in effect for a sharp turn, a bridge, or a similar hazard, that the last car would have to pass the danger point before it could speed up. OTOH, if the slow speed is for a blind crossing, then it would seem that once the engines passed it, the train could start to speed up, since anyone approaching the crossing would be able to see the train already moving through it.

Although I've put this in the miscellaneous discussion area, I would suppose it would also apply to Auto-Train, since it is rather long.

Generally what you say is right, and is probably the same in the US as it is in the UK and elsewhere.

Speed restrictions for sharp curves, bridges etc etc have to be passed by the whole train before you can speed up and crossings where you slow down to ensure that no road vehicles are likely to be on the crossing can be accelerated away from as soon as you are sure the crossing is clear.

On the Class 66 diesel locos in the UK (made by GM) they have a device in the cab where you can enter the train length as you pass over a speed restriction and it tells you when you are clear. I imagine that device may well be used in the US as well? Other than that it comes down to the drivers experience and knowledge of the line he is on.

 

[battalion51]

They do have a distance tool on the computer of the engines. When the head end of the train passes the boards for the end of a speed restriction or a switch usually the Engineer will start the counter. When it approaches the distance they'll begin the throttle up process so that the train is picking up speed as the last car clears the restriction.

 

[DET63]

Is something similar used on most Amtrak trains, or are they short enough for it not to matter?

 

[George Harris]

The rule is generally the same, whether passenger or freight, the whole train must be out of the speed restriction before acceleration begins. There are many other reasons beside speed restrictions that requre the engineer to be aware of the length of the train.

There are some restrictions that are designated as "head end only" where acceleration may begin as soon as the front of the engine clears the point of restriction.

As a practical matter, the acceleration rate of trains is so slow that many engineers fudge on the point at which they pull out the throttle, or at least they used to.