Class 455 Mishap - Battersea Park (07/10)

[edwin_m]

Very rare to see one split in service - and you can be assured that this will be looked at diligently as part of the inevitable enquiry.

Indeed. I'd expect RAIB to investigate this one and one of their most significant conclusions will be whether there is a systemic problem with this type of coupling or it is some kind of one-off problem with the unit in question. Actually I would imagine Southern will already have reached their own conclusion on this by now.

Given the lack of failures so far it's unlikely to be systemic, but I guess it's remotely possible that a component is reaching the end of its fatigue life and more will fail in the same way if something isn't done about it. A one-off failure doesn't necessarily imply poor maintenance. it could for example be a consequence of the unit previously running over something, which might have bounced around underneath and caused some damage to the coupling area.

 

[tsr]

From what I currently know, I believe a preliminary check of the train was done by the RAIB, but I don't know if they've launched a full investigation.

 

[TDK]

I disagree - what he's saying is that it makes sense to continue to use the current coupling design, but impose an "inspect after x hours use" requirement. Seems sensible to me as long as there's a suitably large value for x.

How do you know that the bar couplings are not already inspected on a regular basis, you don't even know the cause yet so therefore cannot construct a valid cure.

 

[najaB]

How do you know that the bar couplings are not already inspected on a regular basis, you don't even know the cause yet so therefore cannot construct a valid cure.

If you look at the sequence of statements, you'll hopefully agree that it wasn't an attempt to create a cure.

BestWestern suggested that the coupling was a poor design - the implication being that they need to be redesigned, Domh245 came up with an idea for an improved design, cyclebytrain pointed out that the proposed design was more complex and would be difficult to maintain and that it made more sense to keep the current design and potentially change the inspection regime, 445driver said that was a knee-jerk response and finally I said that it isn't necessarily a knee-jerk response to ask the question if the inspection frequency might need to be increased.

I also said in a subsequent post that this is all dependent on what the investigation reveals.

 

[craigybagel]

I remember during my guard training we were shown how the uncoupling rod works on a 15x do these trains have a different coupling between coaches?

It is very similar.

But the uncoupling rod is only for the BSI coupler on the unit end, and not for the semi-permanent coupling between carriages within the same unit, is it not?

 

[455driver]

But the uncoupling rod is only for the BSI coupler on the unit end, and not for the semi-permanent coupling between carriages within the same unit, is it not?

Yes it is, I have edited the post you quoted to make it clear.

For info-
The bolted bar coupler between 455s and some 150s is very similar.
The end that is broken is similar on a lot of couplings such as the internal bar, internal BSI, external BSI or external Tightlock, so there are lots of these fixings in use.
It might also be in use on many other coaches/units as well but I haven't had a good look at any of those.

 

[BestWestern]

AS an aside, I'm interested to know why some 150s (from this threat it appears perhaps just /1?) have a BSI between the vehicles rather then a simple bar?

 

[craigybagel]

Yes it is, I have edited the post you quoted to make it clear.

For info-
The bolted bar coupler between 455s and some 150s is very similar.
The end that is broken is similar on a lot of couplings such as the internal bar, internal BSI, external BSI or external Tightlock, so there are lots of these fixings in use.
It might also be in use on many other coaches/units as well but I haven't had a good look at any of those.

Thanks, thought there was something very lacking in my own rod training for a second!

 

[455driver]

AS an aside, I'm interested to know why some 150s (from this threat it appears perhaps just /1?) have a BSI between the vehicles rather then a simple bar?

I think they were all built with BSI couplings I'm the middle (hence the 3 coach sets with a 150/2 coach I'm the middle of a 150/1 set) but some have been fitted with bolted bar couplings recently.

 

[matchmaker]

Excellent pages on class 156 couplings here:

http://members.madasafish.com/~dysgraphyk/156/class156_BSI_coupling.htm

From that it seems that the internal couplings on a 156 (and possibly on a 150) are BSI, but electrical connections are non-automatic.

 

[Chris M]

Does anyone know if the RAIB are investigating this incident? Nothing has appeared on their website yet, and I'd have thought it would have done by now?

 

[TDK]

AS an aside, I'm interested to know why some 150s (from this threat it appears perhaps just /1?) have a BSI between the vehicles rather then a simple bar?

Many class 150/2 still have the BSI couplings between the coaches.

 

[physics34]

.......

 

[BestWestern]

ive heard a very cynical rumour about the incident but i cant quite believe it.... so we'll wait until the report comes out.

Your post would be considerably more purposeful and interesting if you were to offer some insight...

 

[physics34]

Your post would be considerably more purposeful and interesting if you were to offer some insight...

i know, whoops ha ha, i cant say anything. in fact im gonna delete the original post.