What Do Amtrak's "Signal Issues" Entail? - July 3, 2023 Delays on the NY - NJ Stretch of the NEC

TheOneKEA wrote: ↑Sun Jul 09, 2023 6:52 am

Railjunkie wrote: ↑Sat Jul 08, 2023 7:43 am

TheOneKEA wrote: ↑Fri Jul 07, 2023 8:30 pm The Wikipedia article on pulse code cab signaling (taken with a grain of salt, since it could be inaccurate) describes how the actual code pulses used by the ACSES cab signaling system in the trains are injected into the running rails. The key point described in the article is that the pulses are injected using the AC track circuits used to detect the presence of the train. Loss of signal power would not only disable the track circuits but the code generators and injectors too, resulting in the ACSES system displaying a Restricting aspect as described above.

Is there any information on how the signal power loss occurred? My understanding (likely wrong) was that Amtrak had installed a large number of static frequency converters at the various traction substations to provide an alternate power source for the 6.9kV 91.67Hz signal power main that was utility-backed, to protect against a loss of traction power knocking out the signalling systems and the interlockings.

Not a signal maintainer just make them stop and go. Cab signals do work off the code received by the locomotive through the rails. This is done by cab signal pick up shoes over the running rails there could be two or four shoes depending on type of locomotive.
ACSES is a safety overlay and functions with the cab signals, when your trackside and you see those yellow boxes between the rails. They are the ACSES system pucks, antenna underneath the locomotive pick up the signal and display it on the ADU along with our cab signal. The loss of ACSES would not cause the loss of cab signals, although lately with the GEs anything is possible.. One would have to slow down to the prescribed speed depending on railroad either 79 or 59mph retesting the system after 2 miles. The cab signal system will/should function as intended.
As for what when why and how the

Thanks for the additional context! The Wikipedia article on ACSES states that it can function independently of the cab signaling system and explains some of the methods that are used. It also says that ACSES will enforce a positive stop at an absolute stop signal, so I’m curious to know how the ACSES system reacts when the pulse codes go offline while the locomotive is in motion.

Like I said ACSES is a safety overlay it enforces speeds along with positive stops at absolute stops signals. It will also give you a radio release at signals requiring restricted speed. More on that in a bit. The system was designed to function along side of the cab signal system and operates off of high frequency band width radio with receivers along the way. Underneath the engines are antenna that receive information from "pucks" along the route. No worries about the pulse from the cab signal system or lack there off it goes down. .

The better system is I-ETMS, runs off satellite this is used by the freight companies it rarely fails is accurate to about 25ft and a route map is displayed in the cab of your locomotive. It knows everything its like having big brother looking over your shoulder at all times.