QueensCurve
Established Member
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- 22 Dec 2014
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Retrofitting bi-Di is, essentially, a resignalling. So whilst it does save a lot of delay, it wold never be enough to pay for the bidi as a stand-alone investment. Doing it at the time of resignalling is much cheaper - but of course that line hasn’t been resignalled for nearly 50 years.
It was retrofitted (SIMBIDS?) to the GWML about 1989 when I lived in Batheaston with a view of the signals protecting Bathamton Jct.