Re Yesterday's Disruption

I travelled on the Jubilee just 10 minutes before all this happened. I'm so jealous!! Why couldn't I be late for work as usual?

Walking in the tube tunnels is my dream! ;D

Is it not part of the procedure for detraining between stations that the driver placed the SCD onto the juice rails just to be sure?

Just a question, why does it take so long for the line to get back to normal running? If its delayed AM its still running with delays PM, often late into the evening. You'd think with a straight forward line, no branches it would be easier to get back on timetable.

How long does it take to walk a packed tube trains worth of people along a tunnel?

Walking people out of the train is a last resort. One which is not undertaken lightly, however it is one that the staff are trained to undertake.

Procedures were tightened after the train radio failure on the Jubilee Line a couple of years back and no doubt London Underground as well as the Office of rail regulator will be looking at LU's response and will advise accordingly.

Althought today a similar incident that required passengers being walked out of the tunnels, but this time on the Victoria Line. www.bbc.co.uk/news/uk-england-london-11575123

One thing I think is worthy of a mention is that if my bus breaks down, I can tip out, put pax on the following service which will then overtake my bus and all is well. That simply can't happen on rails.

Think of it then as a single track one way road... My bus breaks down, and all the following services are then stacked up behind me. The only way to get to me is down that route from the opposite direction in an illegal move. Permission from various people including the police and highways has to be granted, no doubt supervised as well until I can be recovered. Meantime the whole route is absolutely decimated, and there isn't a spare bus to replace me as they are all in service but stuck behind me. Runs have to be dropped, others running empty to get to required places at required times, others turn short for a connection, and all in order to get the right buses to the right places at the right times.

I certainly don't envy the job of the people in charge of this.

However, with the link provided above, how the service can be regarded as a shambles is quite beyond me..... You simply can't predict a breakdown unless you have a crystal ball, and delays are inevitable as a result of one. Power failures are something well beyond the control of LU in the first place, so how they can be held accountable for yesterday is laughable.

Was the Victoria line problem another sensitive edge issue on the 2009 stock?

Carry them? Get two guys, top and tail the user down the tunnel. ;D

OTOH they could be kept in the wheelchair seating bay with a member of staff/trusted passenger, and wait till the train is shifted to station.

IMHO the latter option is the best.

SCDs should always be put down once traction current is discharged to prevent it from being recharged in error while the detrainment is taking place. However SCDs should not be put down on live current other than in extreme emergency because there is no guarantee they will discharge it and other problems can ensue. I seem to recall an incident on the Picc a few years ago where an SCD was put down on live track and it exploded.

I don't know the full details of what has taken place in this instance but it does sound like it was pretty dreadful for the people involved.

For the record, "carry sheets" are carried on board trains to cover the eventuality of removing somebody that is unable to disembark under their own steam.

It would depend on the circumstances, but the preferred option is to leave a disabled person on the train with a member of staff. Obviously if it's likely the train won't move for some hours they will be taken off, though they would most likely be left until last if the carry sheet option is required.

Slight derivation - but the problem is not with H&S rules, it's with people who think that H&S rules mean you can't do anything!

I'm not aware of any safety rule that says "thou shalt not carry a disabled passenger on a sheet in an emergency". Presumably, someone has done a (cover your ears) risk assessment, provided appropriate instructions to staff, made sure the sheets are of a sturdy enough grade of canvas or whatever.

There was a thread on another forum recently about staff being first aid trained - when a certain transport conglomerate banned staff from rendering any first aid to passengers on the grounds that they took a workplace first aid certificate, not the advanced one which is apparently required to deal with members of the public, so it was too much of an insurance risk.

Presumably in the event of any such disruption any off duty medical staff or transport staff on the train would make themselves known to the driver to assist as required.

We have these brand new stretchers, bright orange. Trouble is they don't fit into the old stretcher cabinets AND I'm told they need some assembly before use. Imagine the ES story, man lies dying on floor while station staff try and insert plug A into hole B. I hope they got Ikea to make the stretchers/ instructions. I can do IKEA furniture.....

I do not believe it was an SCD that exploded (I am aware of many things applied to the current rails that did) but a CRID, in fact that happened more than once. However, SCDs do jump.

As far as SCDs go they are strong enough for the job from the old heavy lumps with folded wooden handles to the several generations of lightweight variety. However, applying an SCD in an emergency is not for the faint hearted. Depending upon the location trying to use one to short the live traction can be fraught with danger. Once upon a time electrical maintenance staff used to routinely use SCDs to test tripping of substation circuit breakers until one night when an SCD threw the man applying it. He made a second attempt with a colleague and the two of them could not hold it on long enough for the breakers to trip. Not long after that event that type of maintenance routine was withdrawn.

The safest way to trip the current is of course by one of the several methods of using the tunnel telephone circuit. I can see no logical reason why you as controller in an emergency could not
request the Electrical Control room Operator to apply the CB inhibitors to affected discharged sections as added insurance against accidental recharge though AFAIK they have never been used except during routine tunnel telephone maintenance.

Interesting, I've never heard of an SCD exploding but I guess if there's enough power to melt one then that would certainly be the visual result as it weakened much as the filament in a light bulb instantaneously pops.

As I say I have heard of all sorts of things blowing up when connected to the juice rails, it was the reason that Signals intercom sets were withdrawn. Many years ago we used to communicate between locations by using the juice rails as a speech pair (with the juice off) and magnetically connecting Eagle intercoms to them until someone put one down without checking the current was off. Shorting strips were also commonly instantly fried by 'road block' men who applied the strip to the juice rails instead of the running rails.

I presume the SCD in question had been put down with the current discharged and then left on when the section was recharged, otherwise I would expect it would've been impossible to place without fireworks in the first instance. I had not considered this in my previous post. Of course the placing of SCDs can be complicated by track parallelling which if not disconnected beforehand will inhibit the effect to some degree, another factor is distance from the substation(s).

It is of course difficult to monitor a traction circuit from the substation unless one has original data against which a comparison might be made but even then with the current drawn by trains when moving from rest and more than one train in a section even that might be tricky so I expect that detecting the presence of an SCD remotely is virtually impossible as it would be seen as just another resistance. I don't know how well the track recording voltmeters react in such circumstances, my recollection is that that give only a rough idea of the general condition of traction supply in a section but things may have advanced in the 20 years since I last looked at one.

Short Circuiting Device?