On 27 Sep, 13:17, Tom Anderson wrote:
We know A-stock can get between Liverpool Street and Aldgate East
(because that's how units get to and from the ELL) - so why can LUL not
divert [some of] the Met service from Aldgate to join up with the
District?

The usual panoply of reasons:

- A stock drivers don't have route knowledge beyond Aldgate Junction (do
they?)

Presumably some of them do, since there's pretty regular rotation of
ELL trains (and indeed, ELL trains are maintained at Neasden).

- Where would you reverse? A stock can get to Aldgate East, but there are
apparently infringements at Whitechapel,

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...

so they'd have to reverse using
the trailing crossover which apparently lies just east of Aldgate East; i
have no idea if it's signalled to make that easy, and even if it is,
that's a reverse on a running line.

- It might be enough additional time that you'd need more trains and
drivers, which might not be available.

- Er ...

- That's it.

Yup, that sounds like it.

In another forum, someone has suggested that double-manning would
solve the problem - it certainly would in a 'actual safety' sense, but
since there's no problem in an 'actual safety' sense I'm not sure how
relevant that is...

--
John Band
john at johnband dot org
www.johnband.org