"Tom Anderson" wrote in message
rth.li...

I thought i'd read somewhere that it was a converted tube train, which
would suggest that it might have retained conventional brakes. However, i
now think i imagined that, and that it was this newish Schweerbau machine:

http://www.rtmjobs.com/rail-news/art...on-uk-railway/

Now, the RAIB press report talks about, at first, a train "designed for
re-profiling worn rails", but then about a "grinding unit", whereas this
is a milling machine, which is subtly different. However, the difference
is subtle, so it might get called a grinding machine by mistake, and i
have also seen it asserted that it is a combined grinding and milling
machine, so it might even be correct.

So, we know that the unit involved in the incident was (a) a rail
re-profiler of some sort, (b) operated by Tube Lines, (c) diesel powered,
(d) working on the Northern line, (e) similar-looking to a passenger tube
train, and all of those fit the train described in that article.

The (pretty small) picture on the RAIB investigation summary page:

http://www.raib.gov.uk/publications/...te_runaway.cfm

....seems to match this one more closely, the RGU 2000.

http://world.nycsubway.org/perl/show?65269

Compare the trapezoidal windows, rather than the new SFU machine's more
rounded shape:

Paul S