Metro-North cab signals

Another question about MN cab signaling...

Do the cab signals downgrade sequentially when approaching Med. speed turnouts?

Such as...

Normal>Lim>Med>Med(interlocking)>Normal

or is it...

Normal>Med>Med(interlocking)>Normal

On the upper Hudson and Harlem I've heard the signals go Normal>Med>Restricting when following another train, so that's not sequentially. But what about when approaching medium turnouts?

I know it is a MN thread but Amtrak's 9 aspect cab signal system
allows for Approach Medium "30." However, I do not know where
there are any wayside installations where this is used.

In almost all cases, the cab signals downgrade in sequence (normal, limited, medium and restricted) approaching a switch that's speed is less than normal speed.

When the cab signal changes from restricting to a to a more favorable aspect the train must run its length before increasing speed. Can the train increase it's speed once passing a CP signal or must it always run its length? To me it seems as if they speed up over 15 mph from a stop at a signal.

Thanks a lot for all this discussion, it is very interesting.

Does the engineer hear a tone when the cab signal changes from one aspect to another?

Virtually all cab-signal systems have an audible alarm that sounds when a less favorable signal is received. I don't think there is any sound when the signal upgrades though.

Keep in mind that on railroads with real signals at interlockings the cab will not change from APPROACH MEDIUM to APPROACH even if the turnout is MEDIUM speed and the home signal is displaying MEDIUM CLEAR. This allows the engineer to flexibly reduce speed from 45 to 30 and then accelerate as soon as his train is clear of the turnouts. I have also seen that the cab signal will upgrade to CLEAR as soon as the engine passes the diverging turnout in question.

Since SEPTA abandonned its fully functional home signals it has been forced to micro-manage trains through its 30 mph turnouts, dropping the cab from APPROACH MED to APPROACH some 2000 feet which has lead to significant operational difficulties. I have never encountered this issue on Metro-North as I do not know of any places where they use 30mph turnouts. Cabs will drop to (L) at the approach block and stay that way through the interlocking.

Metro-North does have 30mph turnouts, CP 5 I'm pretty sure has 30mph turnouts, along with CP 10 & 11 on the Hudson. Controlled sidings in MNRR have a 30mph limit so those are probably 30mph turnouts as well. But near CP 5, 10, 11 the track speeds are 30 & 35 anyway so really no noticeable difference.

Also, Mike the cabs do drop to whatever speed has to be enforced one block before the actual restriction. Read a couple of posts up.

The only 30 mph turnout at CP 5 (MO) is the 2/1 swicth on the Harlem side. All other switches at CP 5 are 45 mph. And before you say the wye switch is part of CP 5..................Its not. It's actually part of CP 6. According the the most recent track chart.

Also, Mike the cabs do drop to whatever speed has to be enforced one block before the actual restriction. Read a couple of posts up.

Well how would you ever know if MN never uses 30mph turnouts. As someone pointed out the only 30mph turnouts that they know of are in sections where the MAS is 30 or 35 so its really a non-issue.

This is the same way MN gets around the issues with freight train stopping distances and their flavour of Rule 562. They simply reduce freight speeds to the point where it isn't a problem any more.

If you ask me MNRR has been pennywise and pound foolish in their quest to save $ on interlocking signals.

Its painfully clear than MNs "go-no-go" signal system is meant to simplify the huge amount of sometimes confusing signals and of course to save some money!!!

Amtrak's 9 aspect units do "beep" on a signal upgrade, but it does
not require to be acknowledged. This is done to prompt you to resume
speed.