On Tue, 2 Oct 2007, Clive D. W. Feather wrote:

In article , Tom Anderson
writes

"on the Moorgate Welwyn Garden City / Hertford North routes contra peak
services (i.e. northbound until 0900 and southbound after 1600) are only 2
tph."

Christ! How the hell does that work? Do most of the trains run ECS back up
north?

The peak arrivals run ECS back up to the northern termini to provide another
with-flow service.

Okay, that's what i suspected.

How much time does that save over running in service?

12.5 minutes.

[Moorgate to WGC: 46 minutes in service, 33.5 minutes ECS.]

Okay. Assuming that the run in service back down is also 46 minutes, and
assuming zero turnaround time at either end, then the length of a half-ECS
cycle (is this what they call a diagram?) is 79.5 minutes, and a fully
in-service cycle is 92 minutes, 15.7% longer. Assuming that two-thirds of
the trains (4 tph of 6 tph) currently do the half-ECS cycle, then that
means going to having all trains running in service requires 10.5% more
trains. So, this pattern is a substantial economy. Will the release of
313s from the NLL be enough to cover that 10.5%? Are there other demands
on those trains too?

tom

--
**** bitches, you know how I swang. I gets my cinna-on at the
Cinna-bon. -- K-Real