I'm not sure if I am reading the LIRR ATC correctly, but there seem to be times when the ATC speed indicator and the HUD speed limit do not agree. The ATC indicator on the train and the HUD always agree, but the speed limits shown by the HUD do not. The ATC might say you can drive at 40mph but the speed limit on the HUD is less and if you drive over the speed the HUD shows then you get penalised. There is also the converse where the HUD shows a higher speed and the HUD shows a much lower speed. If you drive over the ATC speed then you get a penalty brake. I would expect the ATC and the HUD speed limits to always agree. Lirr Hud Lower Than Atc by paul.pavlinovich posted Sep 13, 2020 at 9:27 AM Lirr Hud Higher Than ATC by paul.pavlinovich posted Sep 13, 2020 at 9:27 AM Additionally, there are places (particularly around PEN station) where the ATC jumps from 15 to 60 back to 15 as you move across points/switches/junctions..
That’s correct. The ATC is set by signalling conditions, the HUD by the track speed limits. As a driver you should always follow the lower of the two limits.
No don't worry you are right. The problem is that on lirr route was developped just the atc. The problem is that to drive it without hud, you need the ACSES system that shows you the track speed limit with breaking courve too on the track where you are running. The atc works directly with the signal so as you said if the atc says 60 and after a bit it istantly change to 15 is because normally a mile before the signal the ACSES says you to decellerate from 60 to 15. (Normally the ACSES says a lower or the same ATC speed). Honestly it is really frustating to drive it. You must need the hud to know where is the new speed limit. If you increase the zoom in the middle of the desk of the M7 you can see an indicator that doesn't work with "track speed limit", that is the display of the ACSES that show you the current speed that you don't need to pass. I don't know why DTG haven't developped it. The ACSES works on NEC dlc.
best info I've seen on this, thanks heaps - so many people just say its not wrong, do the lower speed but you took the time to explain it, thanks
For those finding this post a year later... I have run the route and recorded the speeds, slopes and distances. Then made it into this set of charts along with a schematic, and a map of speeds on last page. It's off it some places, but makes driving this route enjoyable, and I don't use any HUDS.