Thursday, 27 February 2014

The Dawlish Diversion

The recent problems with the seawall at Dawlish has left much of Devon and the entirety of Cornwall cut off from the rest of the rail network. This is problematic, but as I said in an earlier post, it is far from the first time it has happened. This week, National Rail released a document that shows some of the damage done by the storms, and the work being done to fix it. The last page includes a low-resolution map showing potential long-term diversionary routes that are being looked at. These include two potential routes (C1 and C3) that have a long history.

Because of the problems with the line, in the 1930s the GWR proposed a couple of alternative routes that would bypass the troublesome coastal route. Unfortunately there is a very big hill called Holcombe Moor in the way, and therefore any line was going to be very heavily engineered.

The first alternative route headed south from Exminster, bypassing to the west of Kenton before heading more or less directly south to Dawlish, where it headed to the west of the town before curving southwestwards under Teignmouth to rejoin the existing line to the southwest of Bishopsteignton. This would require about eleven miles of new double-track railway, and is depicted by the red line below.

The alternative replaced the northern half of that route, leaving the existing line to the north of Dawlish Warren and heading under the town before rejoining the route mentioned above in Dawlish. This route would require seven miles of new double-track railway, but would be subject to tidal conditions along the Exe estuary, and would probably be slower. It is depicted by the light-blue line below.

The GWR got the former plan through parliament, and actually started construction when war interrupted in 1939. Given recent events, many people are thinking of building another diversion line, so I thought I'd take a look at what the GWR proposed.

Thanks to David Brown on the Railform Blog, I've found a map of the proposed routes. This is not the whole story as there were other proposals, but it's interesting nonetheless. I have transcribed the routes onto a modern OS map:

As can be seen, Dawlish Warren and Dawlish will still be able to be served by trains, albeit the latter a kilometre from the seafront. Teignmouth, however, will be more difficult, as the line passes behind the town in a very deep tunnel.

To my surprise, there does not appear to have been a massive amount of development over the last seventy-five years that would stop either of these lines being built. True, there would be some demolition, but not as much as I feared.

Either of these routes would be fast and weather-proof, and would serve the south of Devon with similar service patterns to those that already exist. The line could also be electrified. The downsides that I can see are cost, and the problem of giving Teignmouth a station.

If more information comes out on the C2 alternative in the Network Rail document (which seems to leave from north of Starcross, midway between the two routes above), then I shall do another post.

For another alternative proposal, see

No comments: