Several signal/equipment/operation questions

RC '75,

Just to add one footnote to Clem's post, the application light bulbs blow quite frequently, since they are lit most of the time. Since a ladder would be needed to replace the application light bulbs on an M-1 in a yard, they often ride until the next PI. (M-3 and M-7 application and release lights are accessible from inside the car. Yet, they also often ride with blown bulbs or LEDs 'til the next PI.)

You most likely just saw car(s) with blown application light bulbs. It is far from a rare occurrance.

Tom

Ahhh Tom,

I knew you'd have the explaination -- of course.

Clem

Interesting signal information. Now, what happens when a train has cab signal/ASC failure en route? Is there a signal indication on the LIRR such as NORAC Rule 280a, Clear to Next Interlocking (the "C board" with the seldom-witnessed flashing white light) that tells the engineer to proceed at some restricted speed to the next interlocking without fear of encountering another train?

I believe if a failure were to occur, cabsignaling would drop to a 15 code.

Homo Sapiens,

An "Absolute Clear [block]" indication on LIRR position lights is three straight up and down, flashing. As you said, you don't see these very often.
The rest, LIRR transportation guys are much better qualified to answer. I'll leave it to their expertise. (I'm M of E.)

Tom

edits: corrected typos

KFRG A cab signal failure of onboard equipment has nothing to do with code in rail.
When Cabsignal aperatus fails yes it goes to failsafe mode, or restricted speed, but it even does this if max code is in rail.

I believe if a failure were to occur, cabsignaling would drop to a 15 code.

KFRG Tom,

If you are saying that any failure in either the cab signal or enforcement parts of the ATC system will loop back and display a no code as a safety precaution, the answer is no.
That might make sense, but it doesn't work that way.
Let's say, for only one example of many possible failures, that you're in an M-1 train, tooling along at 75 mph with MAS code. Debris kicks up and tears the cable open from the #5 speed sensor.
This would have no effect on the MAS code you will still have, yet the train's brakes will now apply at anything over 15 mph[due to tachometer check circuit failure from the open - circuited speed sensor]. It's an enforcement system failure, not cab signal failure. But there will be no loopback of that failure to take away the MAS code. The ATC defect will correctly be turned in as "Brakes apply at 15 mph". The Cab Signal equipment section of that train's apparatus can and will continue to operate normally.

Cab Signal part of the system basically just inputs desired maximum speed on a continual basis.
Enforcement part of the system incorporates the actual speed inputs, gleaned in the LIRR's case from gearcase - mounted "speed sensors" [transducers], and the comparator circuitry that takes the desired speed and actual speed inputs and decides if remedial action is necessary.
That's a good two sentence summary of a much more complex system.

Tom

Thanks for the insightful tidbit Tom.

-Tom