Question on Speed Limit Protocol (Prototype vs. Sim)

[fraserm]

Some observations first. Disclaimer: I'm not, nor have I ever been, a real-life railroader of any stripe. Ever since I've been driving virtual trains I've noticed the behavior of speed limits and the overspeed warning as the train's speed limit is indicated as of the end of the train. IOW, the HUD indication will not change unitl the last car passes the speed limit sign. If I were to start accelerating when the engine passes the speed limit sign I would get an overspeed until the last car passed the sign. I was driving a Donner Pass scenario recently where an AI train was on a parallel track, going in the same direction, and it began to accelerate and leave me in its dust as soon as the engine reached the speed limit sign. On a decrease in speed, the decrease indicates as soon as the engine reaches the sign so you have to decelerate in time to be at the decreased speed at the sign. (I get into a LOT of trouble with that aspect of it...)
My question to the community is - what are prototype rules WRT speed limits? Does a 100-car train need to wait until the EOT passes the beginning of the speed zone to begin accelerating (and how does the engineer know), or can the engineer push the throttle as soon as he reaches the start of the speed zone?
Been wondering, is all...

Thanks,
Marc

[artimrj]

You have to wait until the last car is through the speed change. Crossovers are usually a slower speed than the line. If you speeded up after the engine cleared the crossover, you cars would derail, so you have to maintain the slow speed til all are through.

[fraserm]

Thanks, Bob. That's a good point, I'd forgotten about crossovers. So the AI's behavior is not exactly prototypical. This particular stretch of track didn't involve crossovers.
Always learning!

M.

[harryadkins]

AI traffic can be completely prototype as long as the correct speed limits are programmed into each set of tracks. Prototype engineers have an employee timetable that gives complete details about every aspect of the trackage they operate over including specific speed limits.

[mrennie]

I've also read that in the old days, the conductor in the caboose would signal to the engineer when the speed limit sign went past, and that engineers would already know the length of the consist measured in terms of how many telegraph poles they'd pass. I try to do that whenever I do a run on the HSC, which has nicely spaced telegraph poles.
In modern locomotives I've seen something on the cab display that gives the length of the consist and I think there's a button the engineer presses when he passes a speed sign, and the computer works out (based on speed and length of consist) when the end of the consist has passed that same point. Unfortunately, that isn't modelled in TS2013 (although I suspect that there might be a way to do it through specialised controls and clever LUA scripting).

[BNSFdude]

In US trains, the MARY or Wilma as some call it, has a Distance Counter from the point you hit it, it will count in feet how far you've travelled. Once you hit the distance in feet that your train is in length, you've cleared that restrictive speed area. On new units with MFDs, they have it built in.

[fraserm]

Thanks, guys. That's very helpful and interesting. It's more and more fascinating as I gain experience with the sim.

Havin' fun and drivin' trains...


Cheers!
M.

[gleno747]

In modern locomotives I've seen something on the cab display that gives the length of the consist and I think there's a button the engineer presses when he passes a speed sign, and the computer works out (based on speed and length of consist) when the end of the consist has passed that same point. Unfortunately, that isn't modelled in TS2013 (although I suspect that there might be a way to do it through specialised controls and clever LUA scripting).

It is programmed into some of the UK models, like the class 57.

[SCLALINE]

ive seen that cab alert system when i was riding in the cab of Nederlands Spoorwegen trains, kinda neat there is a orange arm on the speedometer dial and when they pass a speed limit change a bell dings and the orange arm moves to the new speed limit