There were two factual errors in the article Chance to test alternative trackbeds ignored (NCE 22 July).
Non-ballasted track was first installed in Britain in 1969, and at that time British Rail led the world with its development of PACT slip-formed paved concrete track.
Second, the 1.35km long double track Heilingenberg tunnel project did not take two days to complete but five months. During this period not only was the track re-laid using the GETRAC A3 asphalt system but the solid rock tunnel floor was lowered by 185mm, the overhead electrification was completely renewed, and new drainage was installed together with a high pressure water supply for emergency services.
The track laying itself was relatively quick and straightforward - production rates for each of the two layers of asphalt averaged 70m-80m per hour, while laying out of the wide, heavy (560kg) sleepers was at the rate of about 330m per 12 hour day.
Bi-directional signalling through the tunnel meant delays to trains were almost non-existent so there was no financial incentive to complete the work in minimum time.
Minimum cost was achieved by the use of single shift working for almost all activities.
Roger Bastin, consultant civil engineer, Scott Wilson Railways, Roger.Bastin@scottwilson. com