How quickly could a switch be re-instated?

[MikeWh]

So the Bexleyheath line is shut for another week thanks to another landslip at Barnehurst. Many years ago I remember engineering posessions resulting in services from London terminating at Falconwood. The other two lines have switches midway along (Plumstead and Sidcup) so it seems quite short-sighted that there is nothing on the third. How quickly could something be done?

 

[Tio Terry]

Not that quickly. It would need quite a lot of design resource from a signalling perspective and there is a national shortage of that resource. So, unless you cancel something else, you will need to join the queue of projects waiting for available resources. That does not even include Civils Design resources, material procurement, physical resources - including plant as well as people - the list goes on and on ....

 

[Bald Rick]

From conception to commissioning, if it was rushed to the top of the pile for everything, money was no object and other schemes could be delayed whilst resources switched around, probably about 3 months. The key issues would be signalling and power design (and checking thereof), and manufacturing / delivery of the switch and crossing units themselves.

 

[DarloRich]

The installation work isnt that hard. What is hard is everything else!

 

[MikeWh]

Thanks for the replies.

 

[Supercoss]

How quick do you want it ?!

 

[Bald Rick]

How quick do you want it ?!

Not approved on the NR network...

 

[Supercoss]

See 7:14 on video clip, not currently approved but has been used on national network WCML Trent Valley

 

[Highlandspring]

That’s Slateford Yard, it’s not NR managed infrastructure.

 

[Supercoss]

Video also available of system in use on WCML 4 tracking 2:48

 

[tsr]

Not approved on the NR network...

Why is that, out of interest?

 

[ComUtoR]

So the Bexleyheath line is shut for another week thanks to another landslip at Barnehurst. Many years ago I remember engineering posessions resulting in services from London terminating at Falconwood. The other two lines have switches midway along (Plumstead and Sidcup) so it seems quite short-sighted that there is nothing on the third. How quickly could something be done?

Firstly, by switches, do you mean crossovers or pointwork to take you from one line to another ?

Secondly, The switches you mention are not really there to take you from one line, to the other. They are there because there are sidings at both locations so you need the points to get you into and out of the sidings.

On the Bexleyheath there is a set of 'switches' to take you over. HOWEVER, and a big and important point is that they are located right at the point where the landslip occurred. If you put a new set of crossovers in at Kidbrooke. It will be just the luck that you will have problems at Eltham. So even if you put more crossovers in or add turnbacks etc. you will still end up in a situation where you cannot run trains.

 

[dtaylor84]

Why is that, out of interest?

"Not approved" is the default state. Unless someone has done work to approve it, it won't be approved...

 

[Belperpete]

Trams have used such systems for many years during engineering works for temporary turn-backs. Saw one in use in Prague back in 2015. The Prague tram version didn't need a gang of people to change it over for normal direction running, which I suspect could be a serious issue with using the First Eng unit for passenger services.

In the photo below (remember right-hand running), arriving trams unload at the tram stop, then simply run forward straight through the temporary point (to where 9087 is standing), and then set back over the temporary crossover to where the far tram is loading ready to depart.
View media item 3328

 

[Bald Rick]

Why is that, out of interest?

Track engineers not happy with it. Derailment risk. Has been used in possessions as has been pointed out, but under trial conditions.

 

[MikeWh]

Firstly, by switches, do you mean crossovers or pointwork to take you from one line to another ?

Yes, I meant crossovers. Trying to be clever and failing miserably.

Secondly, The switches you mention are not really there to take you from one line, to the other. They are there because there are sidings at both locations so you need the points to get you into and out of the sidings.

Agreed, although both are used to facilitate termination when engineering work is taking place elsewhere on the line. The one at Sicdup is used in both directions.

On the Bexleyheath there is a set of 'switches' to take you over. HOWEVER, and a big and important point is that they are located right at the point where the landslip occurred. If you put a new set of crossovers in at Kidbrooke. It will be just the luck that you will have problems at Eltham. So even if you put more crossovers in or add turnbacks etc. you will still end up in a situation where you cannot run trains.

Yes, I'm aware of the crossover at Barnehurst, just like the one at Crayford. Obviously an issue affecting the line near the crossover is not going to be alleviated by that crossover, but one half way along gives you a chance of mitigating the effect of many issues. I have vivd memories of the freight train derailment at Bexley twenty or so years ago. Turning trains at Sidcup was a lot better than just running buses all the way from Hither Green to Dartford.

 

[ComUtoR]

Crossovers have problems. The benefit of having movements into and out of sidings is that you can use any train length (up to the sidings limit) and the movement will be signaled in both directions.

In all my years (10+) I have only ever done the move at Crayford once and you have to be assisted or in a single unit (4/5 car) This will impact any operational benefits. There are other moves across the network that require the use of a Handsignaller and the points operated manually. There are numerous shunts that I have never done and doubtfully will ever do. I think it is safe to assume that having numerous crossovers are just not financially viable. If you consider that an incident can occur anywhere, then the only real solution is to have a turnback move after every station along the line.

If you look at Barnehurst, it is convenient because of the loop into Slade Green and allows for shunt moves into and out of the depot. Same with Crayford. Because of the spur it gives you the ability to loop back into Slade Green and Dartford. Anything else is superflous and generally sits there and gathers rust.

Lewisham
Blackheath (potential diversionary)
Kidbrooke
Eltham
Falconwood
Welling
Bexleyheath
Barnehurst (strategic turnback) (loop)
Dartford


Where are you going to stick a new crossover/turnback facility ? If you are running a service to and from Dartford then regardless of where you turn a unit back you will still end up running a bus replacement service. I would say that having the more strategic turn back being as far as possible on the route will provide the best mitigation. Running the entire Bexleyheath down to Barnehurst keeps that line open and anyone requiring Dartford has two routes as an alternative.

I would like to say that the landslip is a one off and just dumb luck that it is London end of the turnback but it is another re-occurrence and will happen next year or the year after. What I would prefer the money for a new turnback, that will rarely get used, be used for is to fix that entire section of track for the long term and prevent it happening again. A quick 7 day closure fix is certainly better than 8 weeks of disruption but I can't help feeling like its a cheap patch job till it slips again.

 

[MikeWh]

I understand everything you are saying and agree that you can't mitigate every incident. Sadly I also concur that this quick fix will likely break again. I guess the rusting crossover also increases maintenance costs for the line as a whole. Yes you'd still have to run buses for part of the line, but the shorter the stretch the fewer buses are required and the quicker the delayed journey gets completed, especially in rush hours.

 

[DarloRich]

Video also available of system in use on WCML 4 tracking 2:48

that has to be a site in possession. It is NOT in use on the live railway with live passengers!

 

[Dr_Paul]

That has to be a site in possession. It is NOT in use on the live railway with live passengers!

I think that this device would be very useful in permanent-way work or more generally for one-off emergency work, but not for regular passenger services. It would take the weight of 66 diesel and loaded wagons a few times a day, but I wouldn't like to vouch for its durability and the state of the track underneath it with a quarter- or half-hour service going over it all through the day.

 

[DarloRich]

I think that this device would be very useful in permanent-way work or more generally for one-off emergency work, but not for regular passenger services. It would take the weight of 66 diesel and loaded wagons a few times a day, but I wouldn't like to vouch for its durability and the state of the track underneath it with a quarter- or half-hour service going over it all through the day.

Agreed - I am fairly certain it inst suitable for use in a real life situation.

 

[Tio Terry]

I think that this device would be very useful in permanent-way work or more generally for one-off emergency work, but not for regular passenger services. It would take the weight of 66 diesel and loaded wagons a few times a day, but I wouldn't like to vouch for its durability and the state of the track underneath it with a quarter- or half-hour service going over it all through the day.

Whilst it may be of interest during p way work it is doubtful it could be used in normal service. Signalling system alterations would still be required.

 

[Belperpete]

I think that this device would be very useful in permanent-way work or more generally for one-off emergency work, but not for regular passenger services. It would take the weight of 66 diesel and loaded wagons a few times a day, but I wouldn't like to vouch for its durability and the state of the track underneath it with a quarter- or half-hour service going over it all through the day.

The one I saw in use on the Prague tram network had a far-more frequent service using it, admittedly not with a class 66 and loaded wagons.