London Banter - View Single Post - First train from Cambridge for off-peak fares?

Roland Perry · August 15th 14, 07:46 AM posted to cam.transport,uk.transport.london

In message , at 19:15:56
on Thu, 14 Aug 2014, remarked:
I know this is complicated for Cambridge to London, with the 09:20 available
for off-peak day returns

That's because it uses the rule "arrives in London after 1000"; the 0850
arrives too early at 0944.

but off-peak returns not valid till 09:30,

The planner I'm looking at also offers the 0855, but that's not
consistent with the published rule, which says that train is only for
people boarding at Foxton, Shepreth, Meldreth and Ashwell & Morden.

meaning the 09:50 is the first available train these days since the
09:30 is now the 09:27.

Looking up a day return fare across London via Victoria I noticed I was
offered journeys via the 09:27 but not via the 09:20.

Is the rule different for trips across London via SN? I was looking at
Cambridge-East Grinstead if it matters.

Yes, different rules: SVR rule 5M and CDR rule Y4.

5M and Y4 have a starting-station rule, viz leaving Cambridge from 0855,
rather than the usual "arriving London" rule.

Other SN destinations (East Croydon, Crawley, Littlehampton)

CDR East Croydon is J8 (same rule as Kings Cross); but it's Y4 again for
Crawley and Littlehampton.

seem to offer journeys via both the 09:20 and 09:27 so maybe it is
just connection allowances across London that cause it to ignore the
09:20?

The answer you wanted:

Some planners don't like showing trains which can be beaten by a later
departure. Therefore I expect that with their estimated cross-London
connection times both the 0920 and 0927 end up on the same Victoria-East
Grinstead departure, so they suppress the 0920 result.

But with more trains [than 2tph] available to those other stations from
Victoria, those 7 minutes can make a difference (eg if heading for East
Croydon the 0920 allows connection to the 1102 from Victoria, but the
0927 is bumped to the 1117).

However, if you know that using the 0920 and doing a
quicker-than-they-expect cross-London transfer will enable use of an
*earlier* train from Victoria to East Grinstead, that's perfectly legal.
In this example you'd need to get across London in 40 minutes, which
should be do-able obviously; and the standard allowance is 41!!
--
Roland Perry