DutchRailnut wrote:correct, but trains have been known to pass a red signal.
A Google search led me to the Anding MS 2005 wreck.
I read the pertinent parts of the NTSB report. Human error of course.
The report stated that a positive train control could have prevented the crash.
But here is a very unlikely scenario:
Assuming Metro North Railroad Hudson Line:
According to the sim I am running (TS2019 with Hudson Line add-on, with M7 cab car or P32AC-DM loco).
Dovetail Games Hudson Line wrote: If you enter a new block and it has a reduced aspect (e.g. going from Normal to Limited) then the following happens and must be done by the engineer: An alarm will go off in the cab. The cab signalling will update to reflect the new signal speed and confirm what the new aspect is. If the train is within the MAS (Maximum Allowed Speed) then the engineer must simply press the ACKNOWLEDGE button (Q key) within 8 seconds. If the train is above MAS then the engineer must zero the throttle, move the brakes into 40% application or greater, and then press ACKNOWLEDGE within 8 seconds. (Note: It is not required to be within the speed limit during the 8 seconds, it is only required that the engineer has confirmed to the ATC system that they acknowledge the reduction in aspect and have taken appropriate action to comply with it.) If the engineer moves the brake back out of suppression while still being above MAS then the alarm will sound again and the same procedure must be followed. Failure to acknowledge correctly within 8 seconds means the brakes will go to full service application - however, the engineer can apply the same procedure as above and they will be able to regain control of the train without having to stop. Once the train is under the new MAS the engineer can simply release the brakes and apply throttle as required.
Would it be possible for the engineer to repeatedly follow the above procedure, but never reduce the speed of his train to the MAS for the new signal, until the train reaches the next block at a speed greater than what is permitted, thus causing a crash? I realize that this scenario would require deliberate action on the part of the engineer; something that is so unlikely it could be considered impossible for all intents and purposes. A non-attentive or sleepy engineer would simply miss the cab signal and alerter, thus causing the train to go into emergency.
Although DTG just released the Hudson Line a few weeks ago, the coding most likely does not reflect the PTC (rather than ATC) system that is now in place on the line.
Would PTC be able to stop the train before it reaches the next block under these circumstances?
I guess I'm going to have to run the sim again and see if I can actually 'get away with' this.
From what I have read about PTC, it is a far more advanced system than what is sometimes referred to as 'ATC'. PTC involves radio as well as track signals, and GPS, thus can potentially determine the train's exact location and the appropriate action to take and when to take it. In addition, PTC can be implemented in the absence of any signalling system, using only track and radio signals, and GPS.
Does anyone remember the 'dead man's pedal'? I guess that was only to protect against an engineer who had fallen asleep, or had literally died on the job! It would also prevent a runaway train. I have read that it was common for the engineer to place his toolbox or other heavy object on top of the deadman's pedal, thus rendering it useless.