Denny D’s Did You Know - PTC and Restricted Speed

Did You Know that when using PTC when passing a signal requiring restricted speed, you must be at 16 MPH or slower. Did You Know that when using PTC and operating at restricted speed that the system will not allow you to exceed 20 MPH by even 1 MPH. Did You Know that if the PTC system stops you because you failed to comply with the prompts that it could be handled as a critical rule violation. Did You Know that PTC cannot see a red flag, rear of a train, improperly lined switch, derail that is on, or other obstructions. It is also  still up to you to operate at a speed that allows stopping within half the range of vision. There are few rules to keep in mind when operating at restricted speed with PTC engaged.


Critical Rules

GCOR 18.7 - PTC System Inputs and Prompts (No attempt to slow or control speed)

Simply put, if you fail to control your speed or slow down and the PTC system puts you into a penalty brake application, it is a critical rule violation.


SSI Item 10-B: Positive Train Control (PTC) Operations

Part 9 Operating at Restricted Speed

When Restricted Speed Rule 6.27 is required the following applies:

  • The system will provide a warning at 19 MPH.
  • The system will stop you at 21 MPH.
  • The system will ask for switch alignment approaching hand operated switches.
  • The system will stop you if it predicts an overrun.


GCOR 9.10 Initiating Movement Between Signals

Restricted speed until your leading wheel pass the next signal is required.

  • When entering a block between signals.
  • Previous signal is unknown
  • Movement in the opposite direction from which the block was entered.


Unlike delayed in the block and  next governing signal, there is not an exception for PTC to this rule.


Normally when we swap crews and the crew tells us what the last signal was, we may operate under the delayed in the block rule. However, when operating with PTC, the system does not know what the last signal was. You must operate at restricted speed until you knock down the next signal. This applies even when you get within 1,500 feet of the next signal, the system recognizes that signal, and it shows favorable with a clear block beyond it. It is important not to forget this at Dexter and Jefferson City. You may be able to see the signal through the trees, but there is still a little distance left that you cannot see the track to between you and the signal. A red flag could very well be sitting in front of the signal around the corner.


GCOR 9.11 Movement From Signal Requiring Restricted Speed

When a train passes a signal requiring restricted speed, the train must move at restricted speed until its leading wheels pass the next signal or the end of the block system.


Unlike delayed in the block or next governing signal, there is not an exception for PTC to this rule.


This rule applies whether you have PTC or not. Remember, when you pass a restricting signal, delayed in the block does not apply. I can think of many times when this could come into play, here is one example. On the Chester Sub, a northbound train ahead of you is stopped at the crossing before ICG. To pull up the crossing behind that train, you pass the block signal at 12.2, which is a Restricted Proceed. As that train moves, you pull up to the crossing at ICG. After sitting for a few hours, the signal clears up as well as the PTC system. It is imperative to remember that you passed a Restricted Proceed at 12.2. If you have a light train with a lot of power, it would be very easy to exceed restricted speed before you pass the next signal at ICG. There are many places on the service unit where this scenario takes place all of the time. After sitting for several hours, it can be easy to lose our situational awareness. A conductor I have worked with gave a new hire some good advice to adhere to anytime before moving. Take a minute to regroup. What was the last signal and let’s look at our bulletins to make sure we’re not sitting in or near a slow order or Form B.


18.6.1 Comparison of PTC Display Information

When the PTC display information does not conform with a wayside signal indication, maximum authorized speed, mandatory directive, Timetable, or special instruction, be governed by the most restrictive.


This rule is what keeps us at restricted speed when swapping crews and equipped with PTC. Even though the last crew told us that they came in on a clear and we would normally only be prepared to stop at the next signal. However, the PTC system is keeping us at restricted speed until our leading wheels pas the next signal. Because of 18.6.1 we must comply with the most restrictive.


There is one single most important aspect of operating at restricted speed that is critical to remember. PTC cannot determine a speed that allows stopping within half the range of vision. That is still your responsibility. Keeping these few rules in mind when restricted speed will help us all stay compliant and safe. If you have any other questions about PTC or any other rule, feel free to ask me or a manager.