The recent news that Brighton University is opening a new campus in Horsham (Argus, January 25) must be a further spur to the campaign to introduce a direct rail service from Brighton to the Arun Valley by building a simple chord line below Arundel, a move supported by local MP Nick Herbert.

The present bus service between the two centres ceases after 6pm and takes nearly 90 minutes.

A train service should take less than half that time, particularly if it was only limited stop, say Hove, Worthing, and Arundel – all for the cost of about half a mile of track across a field.

Sadly this does not rate at all though with the proponents of BML2 (second Brighton main line to London). BML2 has created huge momentum with support in the local Conservative Party lobby but it has one irredeemable flaw.

It is designed to be totally incompatible with all present services south of the Thames by being powered by 25kv ac overhead catenary rather than 750v dc third rail.

The costs of modifying the proposed BML2 route across bridges, through tunnels and adapting present rail infrastructure would be staggering and take years, causing disruption.

The power supply would only be compatible with the northern end of BML2’s ‘Stanwick’ link.

Dual voltage stock could be used – Thameslink already switches power supply at Barbican – but this cannot be done on the move, and it takes time for safety reasons.

The stock is also more expensive to build.

Changeover stations have to be wired on both systems.

In order for trains from Lewes to use BML2 Lewes itself would have to have overhead supply.

That could itself cost wasted millions rather than a simple third-rail electrification back up to London advocated by other rail groups like Railfuture. There are cheap viable alternatives like the ‘Arun Chord’ to take pressure off the existing system.

Bob Brown, Ringmer Road, Seaford