track circuit operating clips ?

[Tom]

I've got a set somewhere; I'll double check but I thought they were rated for traction voltages. The negative rail issue is more of a concern/consideration I think.

[greggygreggygreg]

Nov 21, 2023 10:51:35 GMT d7666 said:

Nov 21, 2023 6:43:25 GMT greggygreggygreg said:

Don't think they would stretch far enough on a fourth rail system, as they are only long enough to stretch between the running rails to prevent accidental clipping to the third rail. The fourth rail would be in the way

not sure that is a fully valid argument, since can still bridge 3rd to 4th rails, as well as 3rd to closest running and 4th to closest running rails as those lengths are all shorter than running rail to running rail, the latter being setting the required clip cable length

It is, because the instructions are in third rail areas, to place the first clip on the running rail furthest from the conductor rail. Thereby preventing you from accidentally coming into contact with the third rail.
If in a fourth rail area, the other clip will not reach the other running rail due to the presence of the fourth rail

[d7666]

That video I linked to :



seems to me to have enough slack in the cable to clip running rail to running rail and clear a centre live rail. the 4th rail is not that high enough to take up all that slack.


I'm sure the rules about not using them on 3rd/4th rail lines are correct, but I can't see that "the cable ain't long enough" is any contributing reason to those rules.

[Chris M]

Nov 25, 2023 23:37:58 GMT d7666 said:

I'm sure the rules about not using them on 3rd/4th rail lines are correct, but I can't see that "the cable ain't long enough" is any contributing reason to those rules.

Based on that video I'm inclined to agree, and as they appear to be completely uninsulated avoiding accidental electrocution would seem to be a far more likely reason. However it's not impossible that clips designed for use in third rail areas have a different design - especially as it looks like it would be very easy to contact the third rail when removing the clip.

[d7666]

Yep.

It is possible that regulations may drive cable lengths to prevent certain things from happening, but that is the result FROM the rule, not the cable length making the rule.

[greggygreggygreg]

The cable is deliberately made a certain length in order to prevent it being clipped onto a running rail and the conductor rail, with the Rule Book instructing to place the first clip on the running rail furthest from the conductor rail.
It ain't no coincidence

[philthetube]

I have wondered, however, why LUL staff cannot use them in rail gaps?

[Colin]

Nov 27, 2023 23:56:20 GMT philthetube said:

I have wondered, however, why LUL staff cannot use them in rail gaps?

On LU tracks?

Simple answer is it's a Network Rail piece of equipment for use on Network Rail track only. Track circuit operating clips are only carried on 72, 92 and S stocks because they are the only one's that operate on or parallel to Network Rail tracks.

It's not a valid method of protection on LU and is not mentioned in LU's rule books.

[zbang]

Nov 27, 2023 23:56:20 GMT philthetube said:

I have wondered, however, why LUL staff cannot use them in rail gaps?

If you're referring to gaps in the traction current rails, these won't have the current carrying capacity to move a train without melting. There's also a question of the "advisability" of connecting two different sections; quite inadvisable in most cases IMHO.

(My opinion, but probably accurate.)

[d7666]

Nov 28, 2023 18:00:45 GMT zbang said:

Nov 27, 2023 23:56:20 GMT philthetube said:

I have wondered, however, why LUL staff cannot use them in rail gaps?

If you're referring to gaps in the traction current rails, these won't have the current carrying capacity to move a train without melting. There's also a question of the "advisability" of connecting two different sections; quite inadvisable in most cases IMHO.

(My opinion, but probably accurate.)

I was puzzled by the question anyway. Even if track circuit clips were part of LU procedures on LU tracks, the probability of actually needing using them exactly in the short section that forms a traction rail section gap would be too small to be considered.

[d7666]

Nov 21, 2023 21:49:32 GMT Tom said:

I've got a set somewhere; I'll double check but I thought they were rated for traction voltages. The negative rail issue is more of a concern/consideration I think.

I'd believe too they almost certainly are rated for traction voltages simply because of the risk of making contact with a conductor rail, deliberately or accidently. No matter what rules there are and what training is given, the "there is always one" principle will apply.

[Chris M]

Nov 28, 2023 18:00:45 GMT zbang said:

Nov 27, 2023 23:56:20 GMT philthetube said:

I have wondered, however, why LUL staff cannot use them in rail gaps?

If you're referring to gaps in the traction current rails, these won't have the current carrying capacity to move a train without melting. There's also a question of the "advisability" of connecting two different sections; quite inadvisable in most cases IMHO.

I think the question was about connecting the running rails to each other in the traction current rail gaps (i.e. where there is no danger of them coming into contact with high voltages), rather than connecting them to the current rails. Connecting a "gapped" train (i.e. one that has stalled with all shoes in the traction rail gaps) to the power is done with different leads, known as jumper leads iirc. These will almost certainly be thicker, insulated, and have two different ends (one to attach to the current rail, one to plug into the shed lead receptacle on the train). I can't find many pictures of them, but this supplier]this product page shows the current rail ends (of this product, I don't know if that's standard) and states they are 50mm².

Connecting two different current rail sections is not something I imagine should be done by t-ops in any circumstance.

[DWS]

The Rail Gap jumpers in your photo are the modern type that LUL use they have a magnet to hold them on the current rails, Red is positive, blue is negative. Only staff who are trained and hold a license can use them. The Orange boxes are CRIDs (Current Rail Indicator Device) again you need a license to use them.

[Tom]

I've pruned a number of posts in this thread where the discussion went a bit off-topic and got a little heated. Please try to consider the perspective of others when you post.