Sir - In RG 4.00 (p235) you reported the development of the Non-Electric Locomotive as a prototype high-speed traction unit for Amtrak. NEL is a very interesting approach introducing a powerful gas turbine producing 3140 kW for traction. However, knowing the track standard and considering the numerous sharp and irregular curves on the successful US private freight network outside Amtrak’s Northeast Corridor, I must raise some questions related to safety and track/train dynamics.

First, the nominal static axleload of 24 tonnes is considerable for a locomotive intended to operate at 250 km/h on US freight tracks. Then the discussion, claiming that the rigid bogie (to the same design as the Acela) should be ’designed to operate in revenue service at up to 230mm cant deficiency’ is somewhat thrilling.

The reason for my reaction is the fact that when Amtrak management and the Federal Railroad Administration started 10 years ago to plan for a new generation of high-speed operation on the Northeast Corridor, they launched one of the most advanced R&D projects in North America, with finance provided by the FRA.

The findings are officially presented in two reports from a recognised independent research institute and are available from the FRA. For several months two trains, one with rigid bogies and one with radial steering, were fully tested and thoroughly evaluated. The conclusion was that to safeguard over 153mm cant deficiency on the NEC, including the Philadelphia - Harrisburg route, radial steering must be considered. If this is adopted, it is possible to operate safely with cant deficiency up to 305mm, provided that the passenger accepts lateral acceleration of 0·2g!

I certainly welcome brave new ideas in the often too conservative railway world. Therefore I know many of my colleagues will share my curiosity to see the results from tests with instrumented wheels in the same curves and under the same conditions as the DOT/FRA tests.

Per-Erik Olson

Stockholm, Sweden

Former Director SJ R&D Track/Train Lab and consultant to Amtrak

Level 3 concerns

Sir - You write in RG 6.00 p333 (’Level 3 slips over the horizon’) that ’the technical challenge presented by moving block systems that rely on radio data links is only now being appreciated’.

I have to say that in Britain, following the adoption of transmission-based train control for the West Coast Main Line in 1996, senior signalling engineers in manufacturing industry frequently queried the practicality of the technology and its ability to cope with basic signalling principles.

Such objections were, of course, dismissed by proponents of the wonderful new technology that would solve capacity problems. Not for the first time the railway establishment view has suddenly changed from being reactionary to the new orthodoxy.

Roger Ford

Editor, Rail Business Intelligence

Welwyn Garden City, Great Britain