Commuters trapped in train tunnel as train split's in two

[Gavin-D]

Hundreds of passengers are trapped in a tunnel in south London after the train they were on split in two. The 1745 BST Victoria to Rochester train had just left the platform at Sydenham station at 1830 BST when the connection between carriages broke. Five carriages remained at the station while another five were pulled into the nearby tunnel. Southeastern Trains has said that engineers are on route to pull the train back into the station. No one is believed to have been injured during the incident. Taken from: http://news.bbc.co.uk/1/hi/england/london/7672721.stm

[Pompeyfan]

so basically its a case of somebody accidently uncoupling the two units?

[mendes]

Is anyone working on an activity highlighting this event?

[danielw2599]

so basically its a case of somebody accidently uncoupling the two units?

I believe there are safeguards that prevent anyone actually uncoupling the units while the train is in motion. Its more likly to either be a fault with the coupling itself, or the units were not attached correctly.

[jtiffin]

Don't you mean Sydenham Hill?

[chriscooper]

I don't think there are any safeguards in place to prevent someone uncoupling a train whilst it's moving, it's just a button which energises a solonoid that unlocks the coupling. The button has a lift up guard on it, so can't be accidently pressed, and uncoupling can only be done from the cab next to the coupling, which when the train isn't moving would normally be unocupied and locked, which provide enough safeguard against uncoupling whilst moving in themselves. Most likely it's a mechanical failure, either physically with the coupling or electrically with the uncoupling mechanism (it's happened before with Sprinters where water has shorted out the circuit and caused the coupling to unlock). Oviously there is a chance that the units arn't actually uncoupled. Oviously this would be noticed as soon as the train as the train moved. Also after coupling with any automatic coupler drivers should always attempt to pull back to make sure the coupling is secure.
It's always hard to draw much from these articles, which to say are often inacurate would be a major understatement, but it is interesting that it seems one half of the train made it into the tunnel and the other half stayed in the station. For a start, as soon as the coupling broke the brakes should have been applied on both halves, and since they should at that point have been moving at the same speed they should have stopped pretty much together. Secondly, with a multiple unit, there shouldn't be much stress on the couplings anyway unlike hauled stock, unless the back unit lost traction or power (bad conductor rail contact), both very possible in the current conditions, but even that's not going to be that stressful and couplings should easily cope with it.

[richard222]

Am I missing something?

Why couldn't the driver re-reverse into the station and attempt to re-couple?

[mattvince]

Firstly the train was moving at a degree of speed, having called at Herne Hill (next stop Beckenham Jn), so the rear unit came to a halt in Sydenham Hill with the front in Penge Tunnel after the emergency brake applied. Secondly, in cases like this, it's often advisable to keep the units separate after such an incident, in case there has been a mechanical failure within the coupling mechanism (which would only cause a repeat event a few miles further on), and to avoid potentially 'destroying' any physical evidence as to the cause of the uncoupling. Thirdly, we don't necessarily know if there are any stress factors - for instance the rear unit being on 'half-power' - something which will be investigated as a matter of course.

Finally - it's a Networker. With 'high-quality' BR/NSE Tightlocks. The design is notorious for splitting en-route - just ask WAGN/FCC - although the 465s don't seem to split as regularly, probably as they have fewer instances of coupling for the size of the fleet, and very little coupling in service. More modern units with Dellner couplers tend not to come apart, as the couplings have internal microswitches to validate that the coupling is correctly locked - with the Tightlocks, it's a case of making sure the 'tell-tale' markings on the side of the coupling are lined up correctly (which is not an easy task).

[richard222]

Ok. Fair point, well made, but surely, even if the trains couldn't be coupled, why couldn't the driver drive the train back to the station rather than wait 90mins for an engineering train to pick it up

[6rdfar90]

Health and Safety im guessing

[richard222]

Yeh i guess,

Isn't that overkill - surely it's safer to reverse them out rather than wait 90mins?

[ianmacmillan]

It's the blame culture.

The scene needs to be frozen in time until they find who is to be hung for the crime of uncoupling the units.

[danielw2599]

It all really depends on the situation and to be honest, the details on the BBCs report are very sparse.

Depending on distance travelled, you cant just send the train back the other way as you will be going in the wrong direction for that line. You have to put in certain safety procedures to facilitate that move, particularly if the train needs to traverse points and crossings etc etc. Then you have to think about what damage may have been caused when the train split, such as damaged brake hose/equipment causing the brakes to stay "hard on" (no funny jokes please ) or damaged to electrical eqiupment resulting in power loss. This is where the engineers/fitters will be needed to make the train fit for travel, and Enginners trains would not be used to take the train back.

[glasgowworks]

It all really depends on the situation and to be honest, the details on the BBCs report are very sparse.

Depending on distance travelled, you cant just send the train back the other way as you will be going in the wrong direction for that line. You have to put in certain safety procedures to facilitate that move, particularly if the train needs to traverse points and crossings etc etc. Then you have to think about what damage may have been caused when the train split, such as damaged brake hose/equipment causing the brakes to stay "hard on" (no funny jokes please ) or damaged to electrical eqiupment resulting in power loss. This is where the engineers/fitters will be needed to make the train fit for travel, and Enginners trains would not be used to take the train back.

Even reports about trains are from BBC News nowadays. "Finger on the pulse"

[mattvince]

For anyone still interested - there is a probability that this was caused by an air piston within the coupling becoming stuck, consequently the coupler did not properly engage and lock.