Slow Approach at Paoli

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Slow Approach at Paoli

Postby Lackawanna565 » Wed Oct 22, 2014 10:47 am

I came across a video on Youtube. One of the ACS-64 was out for a test run. The train got a stop and proceed then the signal upgraded it self to slow approach. I thought it would show medium approach. There isn't a short block length. It's 1.6 miles to the next signal heading east. I guess the signal system is still setup from the PRR days. The one rule book from the PRR. They didn't have medium approach. Just slow approach.
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Re: Slow Approach at Paoli

Postby mvb119 » Wed Oct 22, 2014 5:04 pm

This goes well before my time on the railroad, but it was my understanding that the Pennsy didn't have flashing signals, or if they did, it did not come until much later in the game. That is why the old Approach Limited and Limited Clear signals used to have triangles next to them to denote that they were upgraded from medium speed to limited speed. With a Slow Approach, slow speed only applies until the entire train clears all interlocking or spring switches, then Medium Speed applies. So as far as speed goes, you're really not losing much by having a Slow Approach instead of a Medium Approach. The train is still going to have to approach the next signal prepared to stop.
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Re: Slow Approach at Paoli

Postby Statkowski » Thu Oct 23, 2014 7:28 pm

So as far as speed goes, you're really not losing much by having a Slow Approach instead of a Medium Approach. The train is still going to have to approach the next signal prepared to stop.


You are losing time. The train had already approached the Stop-and-Proceed preparing to maybe stop, then proceed at restricted speed (< 15 m.p.h.) throughout the entire length of the block. Had the Stop-and-Proceed clear off to Approach, the train could have proceeded at medium speed (not exceeding 30 m.p.h.) instead of the slow speed (not exceeding 15 m.p.h.) that it received with the Slow Approach.

In either case (Slow Approach or Approach), only one block ahead was clear.
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Re: Slow Approach at Paoli

Postby mvb119 » Fri Oct 24, 2014 1:04 am

Statkowski wrote:
So as far as speed goes, you're really not losing much by having a Slow Approach instead of a Medium Approach. The train is still going to have to approach the next signal prepared to stop.


You are losing time. The train had already approached the Stop-and-Proceed preparing to maybe stop, then proceed at restricted speed (< 15 m.p.h.) throughout the entire length of the block. Had the Stop-and-Proceed clear off to Approach, the train could have proceeded at medium speed (not exceeding 30 m.p.h.) instead of the slow speed (not exceeding 15 m.p.h.) that it received with the Slow Approach.

In either case (Slow Approach or Approach), only one block ahead was clear.


Once again, as I said, Slow Approach does not mean the train needs to stay at Slow Speed. As NORAC Rule 288 (Slow Approach) states: Proceed prepared to stop at the next signal. Slow speed applies UNTIL entire train clears all interlocking or spring switches, then Medium Speed applies. It was my understanding that the signal upgraded itself just before the train in question passed it, but I could have misunderstood Lackawanna565. If he meant that the train stopped then proceeded and eventually cleared the following block allowing the signal to upgrade to a Slow approach, then I misunderstood. I was simply stating that if the train was already approaching or stopped at the signal and it upgraded to a slow approach before passing it, that the time loss would be negligible compared to if it had upgraded to a Medium Approach. Regardless of whether it was this train receiving the Slow Approach indication or the next train, I stand by my point. If he received the Stop and Proceed indication, and then proceeded at restricted speed, then sure; they lost lots of time haha. But seeing as it was a test train and not a revenue run, it didn't really matter anyways. I was merrily referring to whatever train is going to approach this signal in question and pass it as a Slow Approach. I've got to know at least a little something about this seeing as I used to work with the stuff everyday out in the field before I switched from Signals to the CETC side of things . :wink: Sorry for any misunderstanding on my part.
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Re: Slow Approach at Paoli

Postby Statkowski » Fri Oct 24, 2014 8:42 am

Misunderstandings are what makes the world go 'round. I was thinking AAR rules, not NORAC.

Part of what confuses me is why the signal would clear off to Slow Approach instead of Approach.

Plus, if Slow Approach now means slow speed through the interlocking, what's a Stop-and-Proceed doing at an interlocking?

P.S. I managed to find the video on YouTube. The track in question might, once upon a time, have been part of an interlocking, but now has no switches connected to it. Ergo, the "interlocking" through which one must proceed at Slow speed no longer exists, at least for that track. So, the question now becomes "What's a Slow Approach aspect doing at a non-interlocking?"

And people thought New Haven Railroad signals could be difficult to understand?
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Re: Slow Approach at Paoli

Postby ExCon90 » Fri Oct 24, 2014 2:51 pm

PRR position-light signals are equipped to display both Stop and Stop-and-Proceed. In cab-signal territory a S&P is often displayed for a departing train, since as soon as the block ahead clears up the cab signal will change to Approach; it saves a few minutes over waiting for the signal itself to clear up to Approach. (This happened a lot at North Philadelphia when there was still a passenger fleet, and I saw it at PHIL just recently; a northbound Acela knocked down the Track 2 home signal. Next it changed to Stop-and-Proceed, then Approach, then Approach-Medium, and a Regional came along and knocked it down again.) Of course, without cab signals that would be counter-productive since the train would be held to restricted speed through the entire block.
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Re: Slow Approach at Paoli

Postby mvb119 » Fri Oct 24, 2014 10:33 pm

In my old territory it was common to see the signal upgrade to a restricting once a train cleared the opposing home signal and the next train was being routed to the same track. I am not too familiar with the Mid-Atlantic division side of things, but the stop and proceed indication is plausible. Although the train cannot just start speeding up once his cabs upgrade, he has to either travel 500 feet, or one train length, whichever is greater, past the point where he received a more favorable indication from a restricting in case the cab signal flipped by error.
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Re: Slow Approach at Paoli

Postby ExCon90 » Mon Dec 01, 2014 2:58 pm

In the Keystone Line thread in the Amtrak forum there is a post today from chuchubob showing a controlled home signal at North Philadelphia displaying Stop and Proceed as a Keystone train in push mode passes it (the second-from-last photo).
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Re: Slow Approach at Paoli

Postby JimBoylan » Mon Jan 05, 2015 2:40 pm

Statkowski wrote:Plus, if Slow Approach now means slow speed through the interlocking, what's a Stop-and-Proceed doing at an interlocking?
Stop and Proceed could be used at an interlocking if there is a train in the block before the next signal. Stop Signal would be used to keep the train out of the interlocking and block, no matter what. PRR practice did allow this, and seemed to consider that Stop and Proceed was a more restricting aspect than Restricting!
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