London Banter - View Single Post - Train-numbers on the LU

Thomas Crame · February 24th 04, 06:33 PM posted to uk.transport.london

Richard Griffin wrote in message ...
writes:

(Adrian) wrote:
In normal Binary, 16 is 10000, but in BCD each decimal digit is coded
separately in four-bit Binary, so 16 would be 0001 0110 - which is why
it's called Binary Coded Decimal.

Sorry, my mistake. I forgot about that. I'll have to look at the
programme machine roll and check what is used - I think it just uses
plain binary.

I have the answer, Roger: it is Binary-Coded Decimal.

A few years ago I went on an arranged visit to Cobourg Street Control
Centre and East Finchley Signal Cabin [1] and, being a keen sort of chap,
was invited to write an essay on the visit for the members' quarterly
journal CHTbulletin.

[1] - A group tour run by Cravens Heritage Trains for some of its
members.

I have pasted into this article the relevant section of that essay [with
some minor clarifications -- Ed]. With reference to the question under
discussion, the answer is in the 5th line from the bottom:

---------- begin quote ------------------------

A word about programme machines. Each of these consists of a roll of
"Melinex" plastic with holes punched in it; as the day progresses, the
roll is spooled from one drum to the other past the reader. Saturday and
Sunday information is located beyond the end of the weekday information
on the roll, so rewinding is done at 0200 _only_ on Sunday to Thursday
nights. Each row of holes relates to a given movement for one train (the
machine we were shown was for departures from Edgware).

So how come I've got an LUL engineering standard, last revised in
2000, saying the codes are in octal numbering?

Rewind time (or end of traffic day) on all LT centralised control
systems is 0300, having spent many nights half - asleep waiting for
the appointed hour.

The programme machine is not fail-safe, and will not cause routes to
clear. What it will do is call routes, the decision as to if they will
clear or not is up to the safety signalling.

The other thing I was wondering is how does a programme machine at
Finchley Central call routes for trains departing from Edgware?