workextra wrote:LIRRs traditional signals (PRR PL/ Color lights) are based off the speed signaling logic.
Most aspects gives 2 prices of information to the engineer.
1) condition of the block
2) speed to do at that signal or at the next signal
Agree. The cab signaling enforces those speeds. LIRR even has a couple of "bonus" codes for 60/70mph that are used when there is a civil constraint such as a curve which requires lower speed. Also the #32.7's at Queens.
workextra wrote:A clear is telling you that 1 or more blocks are clear and to proceed at the MAS states in the timetable for that track.
A medium clear (interlocking signal) is telling you to proceed at medium speed (30MPH) (keep it simple here) within the interlocking limits over the said speed switches and to proceed at the MAS after the rest of your train clears the limits of the interlocking.
That is one of the differences, instead of using a Medium Clear, RAS uses "Proceed Cab" and lets the ASC system limit the train to Medium. In either system the ASC is going to enforce Medium Speed, but the older aspects have a corresponding Medium Clear aspect.
workextra wrote:A slow clear is the same as medium clear but now is at slow speed (15MPH)
The RAS aspect system does have distinct aspects for Slow and Restricting, (298C and 298D). I imagine this choice was made because those two rules can have the same speed code - although I believe it is allowable to get up to 30 in the cab if the signal displays slow, that might be a recent change.
workextra wrote:Approach medium is telling you to use this distance wisely to reduce your speed from the MAS down to 30 MPH at the next signal, you don’t need to do 30 as soon as you see the approach medium as some at LIRR currently think, you can pass it at MAs and brake accordingly and be in compliance with its indication.
This may be an actual advantage of the RAS system (or Rule 410 area in general): The ASC speed downgrades are computed to give the highest safe speed for the longest allowable time/distance - which helps throughput. Observant engineers will tend to "preact" to the code change points that they encounter every day, which leads to very smooth operation. I can't think of any system that makes a less talented Engineer drive better...
workextra wrote:There’s a few examples of the information given by the aspect of normal speed signals for which the RAS fails to encompass.
Thanks again, I surely agree that more information is better, but the Newsday article was intimating that the newer system is somehow unsafe - that's the thing I'm trying to work out
workextra wrote:RAS signals are not block signals and provide no indication of the block or conditions ahead, they’re strictly controlled point indicators as to where to stop if the track ahead is lined against you. Still providing no information other than stop and stay here.
LIRR does give a bit more information. Aside from "Stop" you have Proceed / Absolute Proceed / Slow Proceed / Restricting Proceed / Restricting - three more than MNCR. The Newsday article said something about "80 indications" on a position light which seems like a typo!
workextra wrote:They rely on a pulsing code in the rails to provide data to the cab signal indicator which on LIRR is Numbers (signal speeds) not actually signals as was on PRR. So if you have a what should be a “medium clear” on a RAS type signal. Your cabs will drop blindly from MAS to 40MPH (30/40Medium speed in cab signal territory on LIRR) a specified distance ahead of the RAS Location. You will fly into this blind and the brake comes on full service, and you, and your passengers and freight move faster than the train. That’s the problem with this air train type automated operation signal system.
Agree that any hard braking could result in "passengers-off-balance." This is not unlike the current situation in Rule 410 territory which has existed on LIRR for some time, no? (possibly why the beers used to be served in a cup with a straw?!?)
I don't know of any plan to expand the LIRR train control system beyond Speed Control into a driverless "Air-Train" scenario, I don't think that would be a very good idea.