101/102 Signal Aspects

[ExCon90]

I see that the new signals have four lights in a vertical row--green on top, and red second from bottom. Anybody know what the new aspects and indications are?

[ekt8750]

I see that the new signals have four lights in a vertical row--green on top, and red second from bottom. Anybody know what the new aspects and indications are?

They look to be same aspects the MFL and P&W use and actually the green is second from the top:

Lunar (?) - Cab Signals in effect with a flashing light indicating a diverging movement

Green - No Cabs, Clear to the next interlocking (I'm sure there will be rules further governing that), flashing light indicating a diverging movement

Red - Stop

Yellow - No cabs, restricted speed to the next interlocking, flashing light indicating a diverging movement.

[ExCon90]

Thank you--so no more pushing a button at Drexel Hill Jct.? And is the whole thing controlled from 1234 or from 69th St.?

And does anybody but me feel that that degree of complexity is a bit over the top for a suburban trolley? Crossing gates I can see, but the rest of it?

[ekt8750]

Thank you--so no more pushing a button at Drexel Hill Jct.? And is the whole thing controlled from 1234 or from 69th St.?

All of the interlockings will be controlled by 1234. I would venture to guess the Drexel Hill one will be run by an autorouter that can read what route the approaching car is destined for and line the switch accordingly.

And does anybody but me feel that that degree of complexity is a bit over the top for a suburban trolley? Crossing gates I can see, but the rest of it?

Not really, especially given what was there before. Whenever there was a need for single track operations, a complex process would need to implemented in order to run it safely. For one, all of the interlockings with the exception of Drexel Hill were hand thrown, spring switches. Secondly all of the intermittent interlockings along the two lines weren't governed by any kind of signals. That meant when those interlockings needed to be used for single track, operators would have to be stationed at both ends of the single track territory, and cars would have to sign in and out at each point to ensure no two cars were on a collision course with each other. In 2019 that shouldn't still be happening.

The speed enforcement aspect of the system, I can take or leave given that there aren't that many cars out on the two lines at one time to warrant the need for it unless they do have designs for decreasing headways in the future.

[ExCon90]

Yes; I didn't know how often single-tracking was needed. It's certainly obsolete to have what amounts to a manual-block station at each end of single track. (As well as having to back over a trailing crossover besides.)

[ekt8750]

Yes; I didn't know how often single-tracking was needed. It's certainly obsolete to have what amounts to a manual-block station at each end of single track. (As well as having to back over a trailing crossover besides.)

They usually have some kind of maintenance project going on every summer. Also now you don't have to shut down and shuttle bus an entire branch if a car becomes disabled (save for if it bringing down a string of wire). You can just line the switches to by pass it.