LM says that two 177km/h trains can operate in the path of a single 160km/h service because the trains departing London Euston immediately behind a 160km/h service cannot operate at 200km/h, the maximum line speed. LM plans to use this spare capacity, which would otherwise be wasted in the shadow of a 160km/h path.

This creates an additional fast line path in each direction between Euston and Milton Keynes during off-peak periods and up to two additional paths during the peak. LM says that during off-peak periods, additional services can be provided using trains which are otherwise spare because they are only used at peak times, or by splitting an eight-car 160km/h train to run as two four-car 177km/h services.

London – Crewe trains will be accelerated, running direct between Milton Keynes and Rugby (avoiding Northampton) which, according to LM, can be achieved without impacting on other operators' services on this busy line. The extra path between Euston and Milton Keynes is used to maintain a three-train-per-hour service pattern between Euston and Northampton.

This provides a substantial increase in capacity on peak commuter services from London to Hemel Hempstead, Milton Keynes and Northampton while offering extra services and reducing journey times to stations further north. For example from December, London – Rugeley Trent Valley will fall from 2h 16min to 1h 55min, while London – Nuneaton drops from 1h 47min to 1h 24min.

LM's fleet of Siemens Class 350 Desiro emus is currently undergoing modifications to allow operation at higher speeds.

The acceleration project will be implemented in two phases, with the off-peak timetable launching this December and the peak timetable in December 2014, following the delivery of seven additional class 350s from Siemens.