Eastern Railroad Discussion > NS Signals

Could somebody in the know please tell me what the following NS signal configuration means?

X
Y
X

R
X
X

R
X

Key:
X = Dark; Y= Yellow; R = Red

Thanks,

Fritz in Huntsville, AL

approach

basic approach, means be prepared to stop at the next signal. see them all the time here on the Chicago Line.

if you see bidirctional signals on with both sides being yellow, or approach, that also means, no trains on the block. Unless, if u see a signal on green on one side with a red signal on the other, chances are a train approaching. same thing goes for CSXT on ex CR mainlines.

TOMT7x





Bath_wildcat Wrote:
-------------------------------------------------------
> basic approach, means be prepared to stop at the
> next signal. see them all the time here on the
> Chicago Line.

Y/R/R = Y/R = Y

"Approach." Proceed at medium speed prepared to stop at the next signal. (Medium speed is established by rule; it's typically 30 mph.)

As mentioned above, if a two-faced intermediate signal shows an aspect more favorable than Stop (or Stop and Proceed) on both sides, there is no imminent traffic.

As for where you show "X" in your diagram, I would never expect to see more than one lamp lit on an individual signal head -- that's almost always indicative of a malfunction if it happens.

toledopatch Wrote:
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> "Approach." Proceed at medium speed prepared to
> stop at the next signal. (Medium speed is
> established by rule; it's typically 30 mph.)

"Proceed prepared to stop at the next signal" is pretty much the universal lexicon used to define the approach signal indication on U.S railroads. The medium speed qualifier needs a little clarification. Specifically to NS: "Trains exceeding Medium Speed must begin reduction to Medium Speed as soon as the engine passes the Approach signal". In effect, as long as you are "slowing" and prepared to stop then you are complying with the indication, but there is no defined point within the block where medium speed is compulsory. Of course, whatever speed that might be required by/at the next signal would be mandatory. This wording is consistent with CSXT signal rules, probably UP and BNSF as well, but I don't have the latter two sets of signal rules to consult.

It's also fairly typical for a signal requiring a medium speed at the time it is passed to have been preceded by an advance notification of the fact, and this is served by the "Approach Medium" indication. However, in cases where block occupancy prevents this from occurring, such as a train following another train, perhaps through a medium speed siding or crossover, the following train could receive an approach indication to denote slow down and be ready to stop, but if the train ahead vacates the block, it would then be possible for the next signal to display a Medium Approach. Worded as it is though, an Approach indication protects against such occurrences. Also, additional possibilities of "next signal encountered" exist in signal systems that are set up to display Restricting indications. So essentially, an Approach indication is sort of a "Wild Card" in terms of what you "could" be looking at in terms of the next signal when it becomes visible. Having said that you don't try to out think the system, an Approach simply is what it is, and being prepared and able to stop at the next signal is the paramount concern.

It should also be noted that some railroads CTC signal rules do not have a Medium Speed limitation in their definition of the indication, simply prepared to stop at the next signal.

>
> As for where you show "X" in your diagram, I would
> never expect to see more than one lamp lit on an
> individual signal head -- that's almost always
> indicative of a malfunction if it happens.

The former CP in Indiana has some odd configurations where multiple lamps lit on the same signal head is normal. For example, at the crossing of the former CP and the CSX at Dewey, the INRD home signals have three lights with the top and bottom lamps being red and the middle lamp being green. So when this signal displays stop you have two red lamps lit on the same signal head.

At some other locations there are a single head with four lamps on it. If you get a restricting down the mainline you get just a lunar lamp lit. If you have a restricting on a diverging route you will get a red over lunar on the same signal head.

Pretty unusual and not good signaling practice in my opinion.