On 6 Nov, 15:45, Roland Perry wrote:

"The RAIB's initial examination indicates that the maintenance
condition of the road rail machine did not contribute to the
incident."

Hmm, they always speak in code!

Did it have a working brake, but no-one put it on, not even the chap
inside who jumped off at Gidea Park? Or was the brake maintained OK, but
someone had disabled it in a non-maintenance kind of way?

I don' t know, but I have found out some more details. Services from
Liverpool St to Shenfield and beyond were using the Up & Down Main
lines, however the half-hourly Gidea Park terminators were using the
Electric [ie slow/local] lines, and turning round in GP middle
siding. The engineering possession extended from Gidea Park country
end to Shenfield. The trolley ran away (how I don't know) down the
steeply-graded Brentwood bank, out of the possession and on to the
operational railway. I have heard that a 315 had just gone into the
middle siding at Gidea Park when this trolley whizzed by 'wrong road'.

Then the person on board leapt off at GP platform, and the trolley
continued until it came to a stand by West Ham Utd's training ground,
towards Chadwell Heath station. So this had the potential to be a
serious incident, either for trackworkers (cf. Tebay) or for the
driver and pax of a down LST-Gidea Park service.

--
Ken