NORAC rule questions

I'm curious why a train that passes a stop and proceed or a restricting has to run 500 feet or one train length pass a location where a more favorable cab signal or if it doesn't have cab signals. Can't increase it's speed passing a for favorable fix signal. And the other thing I'm curious about. A train without inoperative cab signals passing a limited clear has to approach the next signal at limited speed. And the same thing with medium and slow clear. I know they have to approach the next signal at medium speed.


Thanks for any help!

Lackawanna565 wrote:I'm curious why a train that passes a stop and proceed or a restricting has to run 500 feet or one train length pass a location where a more favorable cab signal or if it doesn't have cab signals. Can't increase it's speed passing a for favorable fix signal. And the other thing I'm curious about. A train without inoperative cab signals passing a limited clear has to approach the next signal at limited speed. And the same thing with medium and slow clear. I know they have to approach the next signal at medium speed.


Thanks for any help!

The situation for the 500 ft rule (or one train length) applies if the train is between fixed signals in CSS territory, and yes, a train may increase speed when it the entire train passes a fixed signal.

It's always been my understanding that the reason for the train-length provision is that if the previous signal (the stop-and-proceed under which the train is proceeding) was caused by a broken rail, and the track circuit is fed from the end toward which the train is proceeding, the cab signal should pick up a more favorable indication as soon as the inductor on the front of the engine passes over the break, but the rest of the train still has to pass over it. Once the train has run its length, that means the last car has made it across, and it's ok to accept the more favorable cab-signal indication. (Of course the engineer proceeding at restricted speed is expected to stop short of a broken rail, but it gets dark at night, and the head and ditch lights may not pick up everything.) If this isn't the explanation, I'd like to know more about it.

Lackawanna565 wrote: And the other thing I'm curious about. A train without inoperative cab signals passing a limited clear has to approach the next signal at limited speed. And the same thing with medium and slow clear. I know they have to approach the next signal at medium speed.

Thanks for any help!

You note that you are curious....and then make a statement. Is there a question forthcoming?

ThirdRail7 wrote:

Lackawanna565 wrote: And the other thing I'm curious about. A train without inoperative cab signals passing a limited clear has to approach the next signal at limited speed. And the same thing with medium and slow clear. I know they have to approach the next signal at medium speed.

Thanks for any help!

You note that you are curious....and then make a statement. Is there a question forthcoming?

Yes. Was tired when I typed it. Why do trains with inoperative cab signals have to approach the next signal at those speeds?

And of course the same thing about the stop and proceed and restricting rule when a train could increase it's speed

Lackawanna565 wrote:

ThirdRail7 wrote:

Lackawanna565 wrote: And the other thing I'm curious about. A train without inoperative cab signals passing a limited clear has to approach the next signal at limited speed. And the same thing with medium and slow clear. I know they have to approach the next signal at medium speed.

Thanks for any help!

You note that you are curious....and then make a statement. Is there a question forthcoming?

Yes. Was tired when I typed it. Why do trains with inoperative cab signals have to approach the next signal at those speeds?

And of course the same thing about the stop and proceed and restricting rule when a train could increase it's speed

I assume you have access to NORAC. Read the indications of the signals you mentioned. Now, apply them to a train without cab signals (which can work in advance of the next fixed signal) and imagine clearing an interlocking and encountering another one at your next signal (for lack of a better term, back to back interlockings). There is your answer. This is why you don't see signals like Medium Approach Limited or Limited Approach Limited etc.

Same goes for the restricting signals. If you lose your cab signals, you lose you constant track occupancy updates. So you are governed by your last wayside until you run the block or if cab signals are working, you run your length.

This is not light stuff. You really need an understanding of the cab signals and how they work in tandem and in advance of the wayside signals and an understanding of the signal indications to tackle this. Without that, we can talk all day and it would make little sense. If you DO have an understanding, then everything I said should makes sense.