Swanage Railway General Discussion

Only 3 cars today as opposed to 4 last week though I think at least 0ne car was uncoupled at Weymouth as there was an ECS move to Jersey sidings following this trains departure.

 

It is usually a 159, last week was the first time it was two 158's. So if a unit was uncoupled it must have been at least a two coach 158 assuming they can run in tandem with a 159.

 

1Z73 London Waterloo to Swanage reported as 73.201 leading with 73.107 at the rear. <BJ>
http://www.realtimetrains.co.uk/train/U55337/2019/08/11/advanced

 

Does the class 73 hauled LU 4TC's electro-magnetic central locking system remain operational on the Swanage branch or does it fail when the 3rd rail derived ETS supply is lost at Worgret Junction?

 

As it is then in a heratige line maybe as there is enough supervision of doors by platform staff (not always now on mainline stations) then the 4TC might be exempt of the need for central door locking between Worgret and Swanage?

 

I do no know the answer but post #3039 explains some of it but does of course not mention how a 73/2 works. The interesting part of your comment is not so much it being a heritage line, but that Worgret to Frome Bridge is still NR and not electrified of course.

 

As I understand, there are no meaningful differences between the 73/1 and 73/2 sub-classes - the 73/2s were the dedicated fleet for Gatwick Express duties. More important are the distinctions between these and 73/0 (the original prototype fleet, which have slightly different behaviour when on diesel) or the two different flavours of 73/9, which are modern re-enginings and turn them into fundamentally different locomotives. I still double-take when seeing class 73s routinely working the Highland sleepers, when their reputation pre-rebuild was for overheating very easily when on diesel for any length of time.

 

next Sunday 18th August at Norden the a Ruston 48Dl narrow guage will be running at Norden Station on the old narrow guage track bed above the station

NOW CANCELLED

 

The 73/1 sub-class relies on 3rd rail to supply ETH and as London Victoria to Gatwick is third rail all the way I see no reason for the 1 to 2 conversion to include separate ETH provision. Indeed the diesel engine has barely enough power to provide traction let alone drive a generator for ETH.

 

Indeed - my understanding was that the chief differences were some minor modifications to reduce the effect of gapping when doing Gatwick Express duties day in, day out.

 

Being electro-diesel locomotives, class 73s should be immune to the effects of gapping as the diesel engine can be run up within a few seconds should gapping occur. When used top and tail with a class 489 GLV which has its own traction motors and pick-up shoes (as was customary for Gatwick Express trains) the likelihood of gapping is even more remote. I understand that there were changes with the power controller resistor banks on class 73/2 to more closely match the power profile of the GLV when working in tandem. Other than that, like you, I have no knowledge of what the subclass conversion entailed.

 

Having a diesel generator doesn't make a 73 immune from the effects of gapping, it merely has a capability to overcome that effect (although this will take time to fire up and move the train). The traction supply does not travel the length of the train, so any shoes on a GLV will not pass power traction power to the locomotive. It is possible to gap all sorts of units in all manor of places (seen anything up to 12 car units gapped in my career).

 

In the year 1980 all electro diesels on the southern were restricted to 60mph.
In 1984 the locos selected for the Gatwick Express were returned to 90mph.

 

This info is available at www.kentrail.org.uk

 

I said immune as (I understand it) the primary effect of gapping is to block the line. Some EMUs have jumper cables with clamps to mitigate this but in the case of a 73 the diesel engine could start within a few seconds and move a stationary locomotive so that at least one of its pickup shoes is in contact with the live third rail.

I am aware that the traction supply does not run the length of the train but as the GLV has both pickup shoes and traction motors it could drag the locomotive over a gap and vice versa.

Edit:
Whilst I find this an interesting discussion I maybe in a minority considering the subject of this thread is the Swanage railway. My original question about central locking on the Swanage Sunday service did appear to be a relevant question to ask here.

 

In 1981, I recall travelling on the late lamented Channel Islands Boat train (using one of those seven-day "runabout" tickets, which, I noticed to my horror, shortly after reaching Weymouth Quay, said "NOT VALID ON BOAT TRAINS"!) and I can assure you, with a 73 on the front between Southampton and Bournemouth, we were gong considerably faster than 60mph.

 

Yeh and!

 

The Sunday special 4tc with the 2 73s under eletric power was going fast in places on the mainline, but slowed down under diesel on the SR line.

 

It was the 0-60 then 60 - 0 over the gaps in the conductor rail coming out of Bournemouth that I remember

 

The LU TC batteries can supply door locking for a few hours.
That’s how it worked in 2017 on Swanage - Wareham Services on the days that ETH loco 33012 wasn’t on the train.
From memory, the TC batts would last 3 days.
TC has new batts fitted earlier this year.