Signals along the way.

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John Ashworth
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Re: Signals along the way.

Post by John Ashworth »

Al, I think we've come across the edit problem before. If I remember rightly, the system only allows a poster to edit a post for a limited time after it has been posted - enough time to pick up typos or other errors, but not to come back years later and change the whole substance of a post. Administrators such as Steve and myself have the ability to edit anyone's post at any time, so maybe if you send Steve the relevant material he can edit it for you.

If Steve doesn't get there first I'll respond on the second yellow and the white lights when I have a few minutes.

And for the record, we do not get annoyed with questions from new members. We love railways, love talking about them, love answering questions and discussing things, so just keep on posting questions! We're happy that the FOTR Forum can be a source of information for people interested in railways in general and African railways in particular.
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Steve Appleton
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Re: Signals along the way.

Post by Steve Appleton »

Al, a "single yellow" light means: "proceed but be prepared to stop at the next signal in advance unless that signal is displaying a proceed aspect. Also, except in areas where two lights are used to indicate a turn-out or turn-in (see below), it may indicate that the driver must proceed at the correct speed to turn-out or turn-in over lower-speed points." (i.e reduce speed and you may have to stop at the next signal).

Two yellow lights displayed together (double yellow aspect) means "proceed at the correct speed to turn-out or turn-in over one of more sets of lower-speed points and that the next signal displays a proceed aspect." (i.e reduce speed but you will not have to stop at the next signal).

A yellow and a green light displayed together (green above yellow aspect) means "proceed at the correct speed to turn-out or turn-in over one of more sets of higher-speed points and that the next signal displays a proceed aspect." (i.e reduce speed but you will not have to stop at the next signal).

The addition of a white light to the display is a little more complicated. It is a kind of warning about the state of the second signal in advance. If the white is displayed together with a single yellow or, in some cases with a green light, this aspect (an "aspect" can be a combination of lights, remember) means "proceed but be prepared to stop at the second signal in advance and that this second signal is less than normal stopping distance beyond the next signal." So, it is a kind of advance warning of the status of the signal beyond the next signal because the next signal if it is set to caution may not provide enough distance to stop at the second signal.

White is displayed together with two yellow lights. This aspect means "proceed at the correct speed and prepare to turn-out or turn-in over one or more sets of lower-speed points ahead (the double yellow part) and be prepared to stop at the second signal in advance which is less than normal stopping distance from the next signal (the white part)."

White light is displayed together with a yellow and a green light. This aspect means "proceed at the correct speed and prepare to turn-out or turn-in over one or more sets of higher-speed points ahead (the green and yellow part) and be prepared to stop at the second signal in advance which is less than normal stopping distance from the next signal (the white part)."

Lower-speed points are those that are not specifically designated as higher-speed points (turn-out speed over these is genearlly limited to 20 km/h). Higher-speed points are 1 in 20 points with a moveable "vee" or else 1 in 12 equal-split points (turn-out speed generally limited to 75 km/h).
"To train or not to train, that is the question"
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Steve Appleton
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Re: Signals along the way.

Post by Steve Appleton »

You are correct, John. Edits can only be made by the poster for a few minutes after posting. Also, the free site that has the images referred to by Al has restrictions on cross-linking - in this case it is to persuade the free site owner to cough up and pay for his site, I think, then those restrictions would be removed - so all I can do is hyperlink to the root directory there.
"To train or not to train, that is the question"
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Al Brough
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Re: Signals along the way.

Post by Al Brough »

Steve, once again, thank you for your explanations. They are really the most helpful explanations and better than ANY other reference on the web.
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Steve Appleton
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Re: Signals along the way.

Post by Steve Appleton »

Al, one last aspect you might like to model is the "goods yard and siding aspect". This aspect consists of the red and one yellow light dispalyed together. The appropriate direction indicator arm will also be illuminated. This indicates that the train is about to be turned out and enter a goods yard or siding and to proceed with caution at not more than 15km/h, follow the instructions of a shunter if present and be prepared to stop short of any obstruction.
In practice, for reasons that I know not, one is more likely to see the one-position light shunt signal operated ("45") as authority to pass the signal than to see this aspect displayed.
"To train or not to train, that is the question"
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Al Brough
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Re: Signals along the way.

Post by Al Brough »

Hi Steve,

Once again, thank you for the detail. Every little bit helps!

Al
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