"John Salmon" wrote in message
...
"tim....." wrote
"Peter Masson" wrote

Presumably bidirectional signalling, to make single line working
practicable while the other line is under maintenance.

Nice idea, except that HSE rules don't allow such operations.

No such rule applies between Northallerton and Newcastle, where late-night
passenger trains regularly run 'wrong line' under SIMBIDS.

I was referring to the bit about working on an adjacent line.

tim