The Anonymous Widower

Abbey Line Passing Loop Proposed

The title of this post is the same as that of an article in the June 2019 Edition of Modern Railways.

Bricket Wood station used to be an important station on the Abbey Line, with grand buildings and a passing loop to allow trains to run a teo trains per hour (tph) service as opposed to the current inconvenient train every forty-five minutes.

Consultants have now said that a traditional passing loop, with a second platform and a bridge would cost up to £10million, which is probably not viable.

The Penryn Solution

The article says this about the consultants’ alternative solution.

The platform at Bricket Wood be lengthened such that trains stop at different ends of a single platform, similar to the solution adopted in Penryn on the branch line from Truro to Falmouth, which would help to minimise costs.

This Google Map shows Penryn station.

Note the long single platform in the station.

This section in the Wikipedia entry called Signalling, gives a full explanation of the method of operation at Penryn.

Truro-bound trains use the northern end of the station (Platform 2), arriving before the Falmouth-bound train, which will pass through the new loop and to the southern end of the platform (Platform 1), allowing the Truro-bound train to continue its journey north. This gives a rare situation in the United Kingdom where trains run on the right, instead of on the left as is usual in this country. Trains are scheduled to depart simultaneously for Truro and Falmouth.

Bricket Wood station already has a platform, that can take a comfortably take a four-car Class 319 train, as this Google Map shows.

Consider.

  • I estimate from Google Maps, that the single platform at Bricket Wood station is currently around 190 metres long.
  • Looking at the map, it might be possible to add another ten metres or so to the platform length.
  • The current Class 319 trains are 79.5 metres long or 159 metres for a pair.
  • It wouldn’t matter, if for reasons of safety, the front of the trains were allowed to extend for perhaps ten metres past the end of the platform.
  • There also appears to be space to put a second track alongside the current single track.

I also suspect, that Network Rail have track design software, that can precisely calculate the size and position of the points, so that the manoeuvre can be safely executed every time.

I very much feel, that a design can be produced, that will staff, passengers and regulators.

Can This Proposal Handle More Than Two tph?

If you look at the timings of the train, it takes eight minutes to run these legs.

  • Watford Junction and Bricket Wood
  • Bricket Wood and St. Albans Abbey

The times are identical, irrespective of direction.

If times are the same after installation of the novel loop. A train will take sixteen minutes plus however much time, it takes to turnback the train to get back to Bricket Wood.

As trains will be running every thirty minutes and both trains will leave Bricket Wood at the same time, the train must be able to run the out-and-back journey from Bricket Wood in thirty minutes or less.

  • The out and back legs both take eight minutes.
  • This means that the turnback time must be less than fourteen minutes.

Currently, turnback times are fourteen minutes or less.

  • If you look at four tph, there is a train every fifteen minutes. As each leg is eight minutes long, it would appear another method of operation will have to be used.
  • If you look at three tph, there is a train every twenty minutes. Would it be possible to turn back the trains in under four minutes? It might be possible, but it would be a tough call.

I would suspect, that for a reliable service, the proposed method of operation has a maximum frequency of two tph.

I suspect, that the only way to get more than two tph, would be to fully double track the route, with two platforms at all stations on the route.

Does The New Track Need To Be Fully-Electrified?

There would be around two hundred metres of new track and if electrification were to be installed, a pair of the current Class 319 trains could provide a two tph service.

Surely Network Rail can manage to put up this amount of new electrification without massive cost and time overruns?

Despite being over thirty years old, the Class 319 trains scrub-up well as these pictures show.

But what could be done if electrification was deemed to be outside the budget? Or it was decided that new zero-carbon trains should be used on the Abbey Line?

Battery trains are coming and there are several trains that can use both electric and battery power under development, in the UK, Europe, China and Japan.

Battery Power On The Abbey Line

Bricket Wood station is 3.5 miles from the Watford Junction end of the Abbey Line and perhaps three miles from the St. Albans end.

In an article in the October 2017 Edition of Modern Railways, which is entitled Celling England By The Pound, Ian Walmsley says this in relation to trains running on the Uckfield Branch, which is not very challenging, as is the Abbey Line.

A modern EMU needs between 3 and 5 kWh per vehicle mile for this sort of service.

So if a four-car electric-battery hybrid train was to handle the whole of the 6.5 mile route, it would need a battery of between 156-260 kWh to go between Watford Junction and St. Albans Abbey stations and back. It would also need charging at one or both ends of the route.

But supposing trains used the current electrification between Watford Junction and Bricket Wood stations to both power the train and charge their batteries.

  • The trains would only be doing six miles on batteries, so the battery would be between 72-120 kWh.
  • Trains would raise and lower their pantographs at Bricket Wood station.
  • No new electrification would be required.
  • If trains needed to top-up their batteries, they would do this using the electrification in the two terminal stations.

It might even be preferential to remove electrification between St. Albans Abbey and Bricket Wood stations to save maintenance costs and improve safety.

Could West Midlands Trains’ Class 730 Trains Be Used?

The current franchise holder; West Midlands Trains has ordered a large fleet of Class 730 trains for services between London and the West Midlands and for local electric services in the West Midlands.

Included are thirty-six three-car trains for working suburban services across Birmingham. These have twenty-four metre long cars, so are eight metres shorter than the four-car Class 319 trains, so they are another possibility, unless their longer car length would cause problems in the Bricket Wood manoeuvre.

Should The Abbey Line Be Transferred To Transport for London?

There have been suggestions in the past, that the route be transferred to Transport for London.

I’ll leave the politics aside, but electric-battery hybrid versions of London Overground’s Class 710 trains, which will soon be serving Watford Junction station would probably be ideal.

As they are dimensionally similar to the Class 319 trains, they may also be able to work the route under electric power.

Conclusion

There are certainly, several affordable ways to improve the Abbey Line.

My preferred solution would be go for the Penryn solution, using a fleet of Class 319 trains.

  • Penryn seems to be working well.
  • Track would need to be re-laid through Bricket Wood station, to add the passing loop.
  • About two hundred metres of extra electrification would need to be erected.
  • There would probably need to be some modification to the signalling, as there was at Penryn.
  • Three trains as a minimum, would be needed, two for the service and one as a spare or as maintenance cover.
  • West Midlands Trains already have fifteen Class 319 trains, so finding a viable fleet in top-class condition, shouldn’t be difficult.
  • If slightly shorter trains could be needed, the trains might be able to be shortened to three-car trains.
  • Staff training would be minimal.
  • The current trains are liked by drivers.
  • The trains would be zero-carbon.
  • The current trains are in very good condition.
  • The current trains even have toilets, which are probably not needed on a six-and-a-half mile journey
  • If say in ten years time, new trains are needed, I suspect there will be fleets of suitable electric multiple units, less than eighty metres long.

It is probably the most affordable solution.

 

 

May 24, 2019 - Posted by | Transport | , , , , , , ,

1 Comment »

  1. […] I did a detailed analysis of the proposals in Abbey Line Passing Loop Proposed. […]

    Pingback by Reinstatement Of The Abbey Line Between St Albans Abbey And Watford Junction « The Anonymous Widower | May 24, 2020 | Reply


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