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1.1 A new link is being planned between the Great Western Main Line (GWML) at Old Oak Common and the West Coast Main Line (WCML) at Sudbury Junction to enable Crossrail trains to run to and from Watford, Hemel Hempstead and Tring, thus creating a new “north-western branch” of Crossrail.
1.2 The track alignment design for the proposed layout at Old Oak Common indicates that it would be physically possible to retain a connection to the Wycombe Single line if required (see extract of drawing C241-PBR-RTDPP-010-000200-AP2 P01 [originally 'Appendix A'] which has been annotated to illustrate the retention of the Wycombe Single).
1.3 This Technical Note examines the operational implications of retaining the Wycombe Single connection at Old Oak Common after the WCML - Crossrail Link is commissioned.
2. WYCOMBE SINGLE - CURRENT USAGE
2.1 The Wycombe Single connection at Old Oak Common West Jn is currently used by only a limited number of trains:
2.2 Trains do not run to/from the Wycombe Single during peak hours, due to the heavy use of the Relief and Main lines between Old Oak Common and Paddington by First Great Western (FGW) trains.
- Chiltern Railways West Ruislip - Paddington: one train a day (Mondays to Fridays) each way. This “token” service to Paddington is provided firstly to retain a passenger service over the line, which would otherwise have to go through the statutory closure procedure, and secondly to retain route knowledge for train crews for occasions when Chiltern Railways services are diverted into Paddington due to planned engineering works or major disruption on the Marylebone route.
- Empty Coaching Stock to/from OOC Depot: a total of approximately four train paths a day for First Great Western and First Hull Trains (it is not known whether all these paths are regularly used).
- Freight trains to/from Paddington New Yard: one train path in each direction; into Paddington in the early morning and out of Paddington in the early afternoon.
- Diverted trains as required: for example, Chiltern Railways trains from High Wycombe etc diverted from Marylebone into Paddington during disruption or planned maintenance (this occurs infrequently).
3. TRAIN OPERATIONS AT OLD OAK COMMON
3.1 The Wycombe single would join the Down WCML Link line north-west of Old Oak Common station (see annotated drawing in Appendix A). However it would be necessary for Up trains from the Wycombe single to run “wrong line” for a distance of up to 0.5km (depending on the track layout at the station) before joining the Up Relief line. A schematic drawing of a possible track layout at Old Oak Common is in Appendix B.
3.2 When the WCML - Crossrail Link is commissioned, the number of trains on the GW Relief lines between Old Oak Common and Portobello Jn (Paddington) will increase, making it more difficult to path trains to/from the Wycombe Single line, particularly in the Up direction as explained above.
3.3 In the peaks there will be 24tph (all Crossrail) on the GW Relief lines between Old Oak Common and Portobello Jn, and it will not be possible for any trains to run to/from the Wycombe Single during these times. During off-peak daytime there will be 16tph (Crossrail) on the GW Relief lines between Old Oak Common and Portobello Jn. It may be possible to provide a limited number of paths for trains to/from the Wycombe Single line, but these would have to be fitted around the Crossrail service.
3.4 By the end of 2024, when the WCML - Crossrail service is scheduled to begin, the current Empty Coaching Stock movements via the Wycombe Single to/from Old Oak Common Depot are likely to have ceased, as the depot itself will have been superseded by the new North Pole facility.
3.5 The freight trains to/from Paddington New Yard are assumed to continue. Crossrail Ltd has developed an operational concept for the movement of these trains within Paddington New Yard. It is likely that the arrival/departure times of these trains will have to be late evening or overnight, to avoid conflict with the Crossrail service.
3.6 Planned maintenance on the Chiltern Main Line in the Marylebone area may result in Chiltern Railways trains being diverted to/from Paddington, but this is likely to be infrequent, and to occur during late evenings and weekends, when the Crossrail service is not operating at peak frequency. Even so, careful timetabling will be required to accommodate the diverted trains.
4. CHILTERN RAILWAYS PASSENGER SERVICE
4.1 The existing Chiltern Railways once-a-day service to/from Paddington could continue to operate via the Wycombe Single, provided suitable paths can be identified. It may be possible to enhance the service frequency, but the service could not operate to/from Old Oak Common or Paddington during the peaks on the infrastructure as currently planned.
4.2 To provide a more effective and frequent link between the Chiltern Main Line and the GW Main Line, it is possible that the West Ealing - Greenford shuttle service could be taken over by Chiltern Railways and extended to/from Gerrards Cross or High Wycombe, with an all-day frequency of 2tph. This would enable new journey opportunities for passengers from the Chiltern stations with a simple change at West Ealing, giving connections to/from Crossrail services to Heathrow Airport, Old Oak Common and central London.
4.3 This new service would require the following infrastructure enhancements:
The existing track configuration at Northolt Jn and South Ruislip would be unaffected, as the Greenford - Northolt double track section would revert to its existing single track formation just south of the junction. See Appendix C for a schematic showing these track layout changes.
- New platform(s) on the Wycombe line at Greenford.
- Possible doubling of the section between Greenford and Northolt.
4.4 If an enhanced peak frequency was required between West Ealing and Greenford (to give a total of 4tph to the branch stations), additional trains could operate between these two places, using the existing “LTE Bay” platform at Greenford Central Line station.
1. The proposed track alignment design indicates that the connection to the Wycombe Single can be provided in the final layout (see annotated drawing extract in Appendix A).
2. Freight trains to/from Paddington New Yard can continue to use the Wycombe Single route, although arrival/departure times will have to avoid conflicts with the Crossrail service.
3. A more effective link between the Chiltern stations and the Crossrail network could be provided by withdrawing the current once-a-day Paddington service and extending the West Ealing - Greenford shuttle service to Gerrards Cross or High Wycombe, operated by Chiltern Railways. (When the Crossrail service on the GW is implemented - and the Thames Valley branch lines are electrified - the Greenford branch will become an isolated “pocket” of diesel operation. It would make sense for Chiltern Railways to provide the service, using its existing diesel fleet possibly augmented by ex-FGW diesel units.)