In July, the UK Department for Transport published "Britain's Transport Infrastructure: rail electrification". It said that an immediate start would be made on electrifying the Great Western Main Line (GWML) between Airport Junction (where the Heathrow Express route diverges) and Oxford, Newbury, Bristol and Swansea; and one of the lines between Liverpool and Manchester would also be electrified.

This is all good news. One incidental benefit of electrifying that particular Manchester - Liverpool line is that trains between Manchester Airport and Glasgow/Edinburgh, currently running "under the wires" for over 80% of their journey, will be able to use electric rather than diesel traction throughout.

An interesting couple of paragraphs (52/3) discuss direct rail access from the west to Heathrow Airport - from places like Slough, Maidenhead and Reading.

This would also be a good idea - it's a prime airport catchment area!

Reading, of course, would be served directly from Heathrow by the Airtrack project - something for which BAA and Heathrow Airport are currently seeking permission (see www.airtrack.org).

Slough and Maidenhead are much more difficult. There is a line from Reading to Staines which would connect into Airtrack to Heathrow - but this bypasses Slough and Maidenhead to the south. The line from Reading through Maidenhead and Slough goes about 4 km north of Heathrow - and running trains from this line into the airport would be tricky.

One solution is to reverse trains at Hayes. That's possible - but it takes up track capacity (because a train crossing from the westbound line to the eastbound line blocks both of them for a while). With Crossrail coming, will there be enough capacity - both at Hayes and at Airport Junction?

So passengers could just change trains at Hayes. As they could now, of course - except that air passengers don't like changing trains, for all sorts of understandable reasons.

Is it possible to hook Slough and Maidenhead into Airtrack?

Well, that's tricky.

There is a line from the GWML at West Drayton to Colnbrook, close to the airport. This was very heavily used for building materials (steel, sand and cement in particular) when Terminal 5 was being built - and this saved the M25 from being gridlocked. One problem is that the junction with the main line at West Drayton faces London and not Slough: major surgery would be needed to create a west-facing connection. Another is that the line at Colnbrook is on the wrong side of the M25 - a non-trivial obstacle. It's not obvious how that could be overcome easily.

Another alternative is a new west-facing junction off the GWML west of the airport and a new line into Terminal 5. Feasible, but not cheap. This was something discussed in the context of serving Heathrow by the new high speed line, HS2, in a report issued recently by IARO (see the Publications page of our main web-site). And is Airtrack being built in a way which would accommodate this?

Paragraph 53 of the report concludes, "The commitment now being made to electrification will have a positive impact on the case for Western rail access to Heathrow, and we look forward to the local authorities and BAA taking this into account in their further assessments of airport surface access requirements". So do I - it's an interesting challenge!