'Formation flying' engineering trains reduce delays in rail works

Joining engineering trains together so that they can complete engineering works faster could help save £250,000 per week in costs by eliminating the gap between completing the works and train services running at full speed, according to Network Rail. The company has for the first time used 'formation flying' trains to carry out simultaneous operations during a repair to rails.

The innovative repair occurred at Sandy in Bedfordshire over the weekend, where a set of switches and crossings – points where trains can switch from one track to another – were being replaced as part of a rail upgrade plan. Normally, where track has been replaced, trains must run at reduced speeds over the new track until the ballast below the line has settled to form a firm bedding. Network Rail typically has to pay compensation to operating companies for the delays this causes.

However, this weekend, the company joined a pair of engineering trains by an umbilical so they ran parallel to each other, simultaneously tamping down the ballast and carrying out dynamic stabilisation of the new track in an operation that simulated 200 trains passing over the new switches and crossings one after the other. This allowed passenger trains to start using the new section at speeds up to 125 mph immediately after the works were completed.