Remotely Controlled Section Switches ?

[dave1]

Feb 15, 2017 0:57:23 GMT Nortube said:

General info.
Connecting (coupling) two traction current sections together was often possible via a (normally open) circuit breaker in the substation.
Eg, if it was required to link the:
Stockwell to Clapham Common SB traction current section and the
Clapham Common to Balham traction current section together, all that’s necessary would be to close a circuit breaker in Clapham Common substation. This would now make one traction current section Stockwell to Balham SB.

Whilst rarely done, coupling up traction current sections in this way means that there is flexibility in the event of a failure in the substation.

A traction current section can be subdivided as necessary by the operation of section switches, whilst isolating switches can isolate a dead end track (e,g, siding) within the current section. Changeover switches can be used in some cases to provide an alternative feed to a section of track (e.g. middle platform, siding, etc.), usually by taking the feed from the other nearby traction current section.
E.g. The middle platform at Morden is normally fed from the Morden to South Wimbledon NB traction current section, but it can be fed from the South Wimbledon to Morden traction current section just be reversing the coupling switch.

Depots and groups of sidings had their own outside switches to isolate and couple-up sections (depot shed roads at Morden and Golders Green also had their own isolation as mentioned by RT).

All the section switches / section isolating switches and changeover switches at ground level on the running line and in the depot / sidings were of the manually operated singe blade type – housed in vertical yellow ‘sentry’ boxes in the open or normally just mounted bare on the tunnel walls.

The exception being the two motorised section switches previously mentioned in Highgate sidings. On reading through my notes, I’d forgotten that Morden had six manually operated “track isolators” (circuit breakers) on site around the depot and were at the start of the feed from the depot to the tracks. Golders Green depot had three.

Morden depot was in a separate sectionalisation area to Morden, but the there was still provision to couple Morden depot to Morden, via two section switches (one for NB and one for SB). Presumably this would be done in conjunction with other isolations at Morden.

The above is based as at eight years ago but, other than the change from manual to motorised operation of the switches, there has probably been little change to above arrangements


see the Switch Types and Circuit Breakers book for general details:
www.microlp.co.uk/Homea/books.html

Nortube thanks for this and the link all very interesting and helpful.

[dave1]

Feb 17, 2017 16:37:03 GMT railtechnician said:

Feb 14, 2017 17:01:19 GMT dave1 said:

Were there any special switches for such things as connecting two sections together and would these still be retained once they have upgraded a line. 

Dave, 

Track parallelling was required where one section might not be able to supply enough power for all the trains on that section, East Acton on the Central and Hounslow on the Picc spring to mind. In these cases E/B and W/B roads were normally coupled together due to the lengths of the adjacent traction sections. Such required additional tunnel telephone circuitry found in the TP huts at those sites such that a T/T operation on either road would trip the traction coupling CB as well as the affected traction section CB without taking out the traction CB to the other road. You may be wondering about T/T in those areas because the greatest parts of the traction sections are in the open but there is enough tunnel (only needs to be a trains length and can be a short as the width of an overbridge!) to require T/T on these very long traction sections.

I am particularly familiar with East Acton TP hut which is on the EB platform as I ran the new T/T cables from Wood Lane to the new Park Royal S/S when we were cutting out Old Oak Common SS under the CLP. Of course later Hounslow was part of my regular signal and comms maintenance area as a Picc TO.

My understanding is that track parallelling would remain a feature of traction supply distribution where long sections require it.

RT TP huts had always caused confusion but with what you have put are much more clearer now thanks.

[Nortube]

I had forgotten about TP hits.

They have them on the Jubilee extension.
One interesting arrangement is at Green Park. I don't know what arrangements are today, but there was what I presume was a hut as it wasn't a substation. The area controlled from the hut controlled six sections:
NB and SB sections north of the hut
NB and SB sections south of the hut
NB and SB sections south of the hut to / from Charing Cross

Each section had its own circuit breaker
A coupling circuit breaker joined the two sections north of the hut to the four sections south of the hut.

All circuit breakers were normally closed, meaning that all six sections were as one.

The area was fed at the north from Hays Mews substation (between Green Park and Bond St) and at the south from Charing Cross and Waterloo substations.

[railtechnician]

Feb 26, 2017 15:19:39 GMT Nortube said:

I had forgotten about TP hits.

They have them on the Jubilee extension.
One interesting arrangement is at Green Park. I don't know what arrangements are today, but there was what I presume was a hut as it wasn't a substation. The area controlled from the hut controlled six sections:
NB and SB sections north of the hut
NB and SB sections south of the hut
NB and SB sections south of the hut to / from Charing Cross

Each section had its own circuit breaker
A coupling circuit breaker joined the two sections north of the hut to the four sections south of the hut.

All circuit breakers were normally closed, meaning that all six sections were as one.

The area was fed at the north from Hays Mews substation (between Green Park and Bond St) and at the south from Charing Cross and Waterloo substations.

It sounds rather peculiar because Green Park is a substation, the current sections being Waterloo-Green Pk W/B, Green Pk-Waterloo E/B, Charing Cross-Green Pk N/B, Green Pk-Charing Cross S/B, Green Pk-Hays Mews N/B, Hays Mews-Green Pk S/B which each have a feed CB to the traction feeder cables. 

One would suspect that all the track parallelling might be done in the substation (built in the old Picc line Dover St station) with coupling CBs, however, it is generally at/near trackside in a separate TP hut. I am unaware of the location of the TP hut at Green Park but it would typically contain T/T relays as well as traction parallelling CBs. Where there is a TP hut a T/T circuit will have the usual TT relay at each substation and another in parallel at the TP hut. A T/T trip should reliably drop all three relays disconnecting the traction feeds from both substations on the affected road and also tripping out its coupling CB to uncouple the auxilliary traction feed.