TfL are seeking authority to order 9 more Class 710 units to cover the Barking Riverside extension and also to allow a fleet shuffle to increase services on the East London Line to 20 tph.
A paper goes to the TfL Programmes and Investment Cttee next week.
http://content.tfl.gov.uk/pic-20171013-agenda-item11.pdf
I haven't quoted the entire paper - just the relevent preferred option below. I trust the mods are content with this as the paper is several pages long.
Paper to next week's Programmes and Investment Cttee is seeking approval for extra class 710 EMUs. TfL want to order 9 more units to cover the extras needed for the Riverside Extension plus more to allow the ELL service to increase to 20 tph. There would be 3 extra 4 car units for GOBLIN and 6 5 car units for the NLL / WLL to release 378s to the ELL.
The order has to be placed by 26 Oct to ensure best price and leasing terms. The paper even talks about the trains being "spot hired" in the short term to other operators given they won't be needed immediately (assuming they turn up in 2019) or to use on a supplementary service on the WLL. Looks like TfL are bidding for extra funding to allow signalling and infrastructure improvements at Norwood Junction and elsewhere.
The preferred option in the paper involves some juggling of existing and new stock.
Do something - an option for nine additional trains would be exercised (six 5-car units and three 4-car units making 42 vehicles in total) to enable delivery of the ELL 20 tph and BRE services. One additional Class 315 train would be retained within the broader rolling stock fleet under this option to enable the provision of the planned service level. The steps required to deliver the enhanced services on the BRE and the ELL under this option are described below:
(i) the six additional 5-car units ordered would be used to deliver the NLL/WLL service, releasing six 5-car Class 378 units to deliver the enhanced service level of 20 tph on the ELL;
(ii) one of the additional 4-car units ordered would be used to deliver the Watford to Euston service. Another 4-car unit would be released for use on the same service by leasing an additional unit to run the Romford to Upminster service. A further two 5-car Class 378 units could then be released to deliver the enhanced service level of 20 tph on the ELL;
(iii) eight additional 5-car Class 378 units would therefore be released to the ELL, enabling the 20 tph service enhancement to be operated. This enhancement has to be run using Class 378 units due to the operational and safety constraints imposed by operation through the ELL Core; and
(iv)the remaining two additional 4-car units would be used to deliver the BRE service. The unit availability required under this option would be underpinned by the withdrawal of the additional peak service on the Gospel Oak to Barking route that is referred to above.
During the period prior to the introduction of the enhanced service on the ELL and the BRE the trains could be used on the WLL and potentially elsewhere on the network to help defray any sunk leasing or maintenance costs.