Can someone confirm for me that the mysterious "TPP"-Balloon on the speed/aspect display unit on the F40PH-3C loco (and the CTC cab car) in the Boston Sprinter DLC (see picture below) should actually read "APP", representing an "APPROACH" indication (pulse code 100 Hz: 75 ppm / 250 Hz: – ) as opposed to an "APPROACH MEDIUM 30MPH" indication (pulse code 100 Hz: 75 ppm / 250 Hz: 75 ppm) that is represented by the "30"-Balloon?
I found this picture: in this great article: http://position-light.blogspot.com/2013/06/know-your-cab-signal-displays.html stating: "Many non-Amtrak passenger railroads prowling the Northeast have taken the opposite approach and minimized the signal part of cab signal, arranging the indication lights around the speedometer in "The Clockface" design. ... One remnant of the signal-speed duality exists in the form of both a 30 speed code and an App(roach) signal code pointing to the same place on the speedometer. ..."
At least this would allow for a reasonable indication of the 100Hz/250Hz pulse code aspects, including the 270 ppm rates (that ttbomk are on Amtrak territory only used around NY Penn Station, thus not between Boston and Providence), with slight modification on the upper end of the speed range (that is probably not used by the vehicles in question anyway), plus the "STOP" aspect for the ACSES Positive Train Stop: Anyone around who ever worked with this device in real life?
Yes, MBTA uses an ADU that can display all 9 cab signals (plus stop for ACSES) as originally specified by Amtrak. I have not noticed the “TPP” text until now, but indeed, that appears to be a typo. All other real-world examples I have seen show an “APP” balloon in that location corresponding to the APPROACH cab signal. The 250 hz carrier frequency (overlayed over the legacy 100 hz signal) is not restricted to use around New York Penn. Amtrak uses it wherever high-speed switches are employed that allow for speeds in excess of 45 mph, so for 60 mph - use CAB SPEED 60, for 80 mph - use CAB SPEED 80. Also, it can be used as a “slow-downer” aspect in high-speed or high-frequency trackage (i.e., you may see a signal progression of CLEAR 150, CLEAR 125, CAB SPEED 80, APPROACH, RESTRICTING). So, it should be possible to see these aspects in use between Boston and Providence (and in-game after DTG implements Cactusjuice’s signal fixes soon).
Thank you for the feedback. Just to clarify, I totally agree that the 250 Hz overlay codes are used in the Boston-Providence area. What I said was that the 270 ppm rate codes ("CAB60" and "CLEAR100") are not used there, but only around NY Penn.
This article describes the cab signal progression I mentioned above. https://www.trains.com/trn/train-basics/abcs-of-railroading/ahead-of-the-rest/ Also gives interesting tidbits on the Acela that I hope will be properly implemented for the upcoming dlc.
One would have to see the signal control plans for the railroad to confirm this, but as far as I know, CAB SPEED 60 (270 ppm) is indeed used between NYP and Newark, but I believe it may also be used on between Trenton and New Brunswick in the no-fixed-wayside territory so it is technically possible to see it beyond NYPs immediate boundaries. As for CLEAR 100, I have no clue where it has been implemented, as the examples I have seen show no use for the 270/270 code and I can’t even vouch for it having been used around NYP (perhaps the LIRR uses it?).
From what I have read this is the main reason for Amtrak using the 270 ppm codes around NY Penn, because the track is (partially) shared with the LIRR that uses 270 ppm (and also 420 ppm, I think it was) codes.
Yeah, it makes sense to me that both 270 ppm codes would be introduced for LIRR compatibility. I just have yet to find and example where 270/270 is enforced, even around NYP. Interestingly enough, I understand that a 0/270 code is used for LIRR trains going to the East Side Access tunnels so non-compatible trains (like Amtrak) will get a restricting cab signal indicating that they are routed incorrectly - only the 250 hz carrier is used instead of the 100 hz and 250 hz alternating with each other. http://position-light.blogspot.com/2022/11/the-lirrs-puzzling-esa-ptc-waiver.html
C100 is not implemented anywhere that I can find. CS60 is commonly used in areas where block spacing is especially close (Newark Penn to Secaucus comes to mind). However, you won't find CS60 at all between Boston and Providence.
btw is it just me or is F40PH kinda benevolent towards you keeping the speed limits? not that you get many speed reductions here since track speeds are up to 125 mph and you go only as fast as 80 mph, but still... I get the impression that this diesel machine is kinda more laidback about the whole safety stuff... not that I would like to get penalty brakes all the time, just there is no real tension without all those annoying constant beeps you get in the electrics lol
Here's a photo of the cab signal display of an MBTA Rotem cab car, showing clearly the "APP" label. (In this photo, the cab is cut-out and trailing on the back of the train.) Oh, and I've seen elsewhere some concerns that Speed Limit is often stated as 90 mph but MBTA equipment is limited to 80 mph. It displays this way in real life too. (This display is above the front window on the opposite side of the cab, where the conductor or engineer trainer might stand.) Photos taken with railroad authorization.
