Metro-North cab signals

[playdough]

The Way side signal only has 3 aspects:
Green flashing = proceed by cab signal indication.
Red/red = stop
Red/reg alternate flashing with green = Absolute block (for cab signal failures)

And another (dumb) question: what happens when one of the signal lightbulbs burns out (must happen on occasion, right?). Seems like if the green bulb is out then you might encounter a wayside signal that is completely dark (no lights at all). For the other aspects and/or bulbs, you'd end up with an "aspect" that normally would not be used. What is one supposed to do in this circumstance?

[Patrick A.]

Playdough,
If a signal is out of service, I'm sure MNRR RTC (Rail traffic Control) would issue a directive about the signal and speak with the engineers directly en route while passing the signal. Also welcome to Railroad.net!

Cheers,
Patrick

[Erie-Lackawanna]

An improperly displayed signal is NOT "out of service". It is simply improperly displayed. At an interlocking, an improperly displayed signal must be taken as displaying its most restrictive aspect (on MNR, that would be "Stop"). You would then ask the RTC for permission to proceed past the Stop Signal, governed by cab signal aspect.

Jim

[Penn Central]

And another (dumb) question: what happens when one of the signal lightbulbs burns out (must happen on occasion, right?). Seems like if the green bulb is out then you might encounter a wayside signal that is completely dark (no lights at all). For the other aspects and/or bulbs, you'd end up with an "aspect" that normally would not be used. What is one supposed to do in this circumstance?

The signal lights are part of the cab signal circuit. If the flashing green light burns out, the signal circuit drops and trains would have a restricted cab approaching it. The system will not allow a "surprise" like the old automatic signals that would go dark sometimes. To pass the control point (the only place MN has wayside signals) with an imperfectly displayed signal, you need permission from the RTC, but if the cab signal picks back up, as it usually does in this circumstance after passing the signal, you can resume the speed indicated by your cabs after one train length. No need to go through an entire block at restricted speed unless that is your cab signal indication.

[Anonymous881]

Does Metro-North have the 500 foot rule for cab signal upgrades like NORAC or on Metro-North is it always one train length?

[DutchRailnut]

always a train lenght.
And Like Penn Central said MNCR has Lamp out protection where if the proceed cab were burned out your best cab signal is restricted.
If red indication one or both bulbs are burned out you are already on restricted cab. so either way your approaching signal at a speed where you can and must stop.

[RearOfSignal]

Thanks to both Penn Central and Dutch, I think I finally have it now.

[kitn1mcc]

but with LED less of a Burn out problem

[DutchRailnut]

a bit less but it would be harder to protect and would still need to be protected as LED's are not fail proof.

[RearOfSignal]

Wow, this topic really won't die...

anyway, another question(I'm just very analytical by nature), hope I'm not annoying anyone hear ...

Penn Central you said that you would get a restricted cab ahead of another train, stop signal or end of track. What about when approaching an interlocking when taking a switch or turnout?

| - Code Change
|| - Interlocking Wayside Signal

---->Normal Cab|Limited Cab||Medium Cab INTERLOCKING(Medium Speed Diverging Route)|Normal Cab---->

Would the approach to the interlocking look like this if the train was lined up for a diverging route(30 mph) where the Medium Cab is received after passing the entrance to the interlocking, or would the Medium Cab be received before passing the wayside at the entrance to the interlocking?

Or is there some other configuration of cab signals would be received in a situation like this?

Thanks Again!!!

[Erie-Lackawanna]

You always have the most restrictive aspect one full block behind where the speed must be enforced. Therefore, if the route through an interlocking requires medium speed, then you'd get the medium cab indication one full block behind (prior to entering) the interlocking.

It is this point that had a big impact on train operations when cab signals replaced wayside signals. With waysides, you'd get the "Approach medium" (yellow over green). The indication for Approach Medium was "proceed approaching next signal at medium speed". In essence, you were able to proceed at track speed right up until the last moment you, as the engineer, deemed it necessary to begin braking, so that you'd pass the interlocking signal at medium speed. Now, you begin your deceleration two blocks before entering the interlocking. BIG effect on train speeds.

Jim

[Nester]

BIG effect on train speeds.

Which, as a result, extends the amount of time it takes for the train to travel from point A to point B. Maintaining hundreds of wayside signals may not be worth the minutes you'll save in travel time, but it should be a consequence that is considered.

[RearOfSignal]

So MNRR cab signals or cab signals used in the absence of intermediate waysides act differently than when cab signals are used along with intermediate waysides.

If you took the MNRR signal system and compared it side to side with another cab signal system with waysides but just put bags over the signal heads they would not act the same?

[Erie-Lackawanna]

Actually, once cab signals are introduced, you get the effect I described--with or without waysides. As it happened, though, on the portions of MNR with the most dense traffic, the waysides came out at the same time the cabs were introduced.

Jim

[RearOfSignal]

According to the NORAC rulebook I have(even though it doesn't apply here), Approach Medium and Medium clear both fall under the Approach Medium cab signal aspect which is 45mph when enforced by ATC. In this case the train would be slowed down to at lest medium speed when passing the App. Med. signal but would never be slowed to Medium speed by the ATC since the Med. Clear wayside is enforced at 45mph. Even with Cabs and ATC when waysides are present the engineer still has some level of discretion.

However in MNRR, if lined up for a medium speed diverging route, you would at sometime have to be slowed down to medium speed by the Cabs/ATC before it is actually has to be enforced.

Aha, this is where the difference is, between MNRR and other systems! Finally at Long Last!!!!