Future of Rail | Completing the UK’s first curved box jack Driving the UK’s first curved box jack for a new rail dive under has just been completed on the East Coast Main Line. Freight trains will be the first to benefit from major engineering work at Werrington just north of Peterborough on the East Coast Main Line (ECML) when work finishes in November. Capacity benefits for passenger traffic will be realised when the next timetable change comes into force in May next year, but the effect is expected to be significant. Box jacks have been done before in the UK but never at this length and on a curve. Successful delivery creates the potential for the patented technique developed by Jacked Structures to be used elsewhere.