On Sep 27, 1:29 pm, John B wrote:
According to CULG, they're allowed on the District between Aldgate
East Junction and Upminster. But at this point you would run into
driver knowledge problems...

Given the slothful speed tube trains generally move at I do sometimes
wonder why route knowledge is so important. Obviously on an intercity
train doing 100+ you could easily end up derailing on a high speed
curve if you didn't know it was coming. But whats the worse that can
happen on a tube train crawling along at 20mph thats got tripcocks
anyway? You'd see any curves or points coming up a mile off.

B2003