question on signals

[switchmaster]

I was watching a tv show about railroads and saw a signal that I didn't know. It was yellow over green over red. Any one has any idea as to what it means? I know yellow over green is medium speed till next signal than resume normal speed.

 

[JCitron]

These might help. It depends upon the railroad, but in NORAC rules that would be Approach-Limited.
http://signals.jovet.net/rules/index.html

http://railroad-signaling.com/aspects.html

 

[fec210]

I know on the Florida East Coast Railway, Yellow over Green is approach medium. This means to pass signal at normal speed, but pass next signal at medium speed (usually because a divergent route is set up). Yellow over green over red would be the same, since the lower red is just a place holder in this case.

 

[JCitron]

I know on the Florida East Coast Railway, Yellow over Green is approach medium. This means to pass signal at normal speed, but pass next signal at medium speed (usually because a divergent route is set up). Yellow over green over red would be the same, since the lower red is just a place holder in this case.

That's possible as well. Remember the railroads may have adopted rules from NORAC on the east coast and then made their own modifications. This is the problem with the North American railroads. They may share a lot of similarities, but differences at the same time.

 

[Mkultra04]

That's possible as well. Remember the railroads may have adopted rules from NORAC on the east coast and then made their own modifications. This is the problem with the North American railroads. They may share a lot of similarities, but differences at the same time.

I'm with fec210 with this one, I'm pretty sure on most if not all north American railroads red signals are not only used as stop indications and place holders but also to show speed. Take the slow clear for instance on CSX this is red over red over green, the red signals in this example are used to display speed. Where as in a clear signal, green over red over red, the red signals are just used to show that 1. there are no other aspects to worry about and 2. the other signal heads are working. A good saying to go by is "If it ain't all red, it ain't red at all".

 

[Seane2c]

Sometimes they have dummy reds as they call them as place holders. Anything over 2 aspects is considered absolute, unless staggered or marked by a plate. In some cases a signal number is used to differentiate between an intermediate (proceed at restricting) or absolute which means stop.

Other times those extra heads are used for approach medium aspects or other advanced indications. When you go west to BNSF & UP however they don't use speed as much as they indicate diverging. In Canada here we have a DV plate for diverging on CN for example. This eliminates the speed aspect of the rule and allows you to proceed at track speed (or timetable turnout speed).

Thanks

Sean

 

[JCitron]

I'm with fec210 with this one, I'm pretty sure on most if not all north American railroads red signals are not only used as stop indications and place holders but also to show speed. Take the slow clear for instance on CSX this is red over red over green, the red signals in this example are used to display speed. Where as in a clear signal, green over red over red, the red signals are just used to show that 1. there are no other aspects to worry about and 2. the other signal heads are working. A good saying to go by is "If it ain't all red, it ain't red at all".

That could be I agree, but then again as I said, they may use a variant of the NORAC rulebook. Remember this is only a guideline and nothing set in stone for the railroads to follow. CSX and even NS had to adopt a single system of their own because they merged in a bunch of roads. This system also uses NORAC as a base then it includes variations of their own. The former SCL and ACL had their own signal rules and so did the Clinchfield, C&O, B&O, etc., making this a mess for CSX then they went and merged in the former NYC lines and others up here in the Northeast, which have different rules altogether with the NYC lines using a speed indication. NS faced a similar situation with their Norfolk & Western origins plus the Wabash, Nickel Plate, Southern and relations, and then finally the former Conrail PRR, EL, LV, and others combined.

 

[Mkultra04]

That could be I agree, but then again as I said, they may use a variant of the NORAC rulebook. Remember this is only a guideline and nothing set in stone for the railroads to follow. CSX and even NS had to adopt a single system of their own because they merged in a bunch of roads. This system also uses NORAC as a base then it includes variations of their own. The former SCL and ACL had their own signal rules and so did the Clinchfield, C&O, B&O, etc., making this a mess for CSX then they went and merged in the former NYC lines and others up here in the Northeast, which have different rules altogether with the NYC lines using a speed indication. NS faced a similar situation with their Norfolk & Western origins plus the Wabash, Nickel Plate, Southern and relations, and then finally the former Conrail PRR, EL, LV, and others combined.

Hmm I think I know how we can solve this lol. Hey Switchmaster, what show were you watching?

 

[JCitron]

Hmm I think I know how we can solve this lol. Hey Switchmaster, what show were you watching?

Lol. let's watch a movie.

 

[switchmaster]

Thank you one and all for your input. I guess every railroad signaling is quite unique.

Thanks

switchmaster