Sub-Surface Dot Matrix

[heart-of-wessex]

Hey all,

Why do the Dot Matrix on the Sub-Surface stations show different to tube lines?

On tube lines they have say:

1. QUEENS STREET
2. QUEENS STREET
then to
3. HARROW & WEALDSTONE

but on the Circle/District say they have:

CIRCLE AND DISTRICT LINES

Yes I know where I am but whens the next friggin train! then they only show it when its due in a minute or 2, or maybe show 2 trains if your pushing it.
Are they a different system?

any help appreciated,
James.

 

[Tom]

Depends what station.

The SSL line indicators don't register it until it's passed the last junction on the route.

 

[class 313]

Hey all,

Why do the Dot Matrix on the Sub-Surface stations show different to tube lines?

On tube lines they have say:

1. QUEENS STREET
2. QUEENS STREET
then to
3. HARROW & WEALDSTONE

You mean Queens Park?

 

[Met Driver]

Depends what station.

The SSL line indicators don't register it until it's passed the last junction on the route.

Doesn't just happen on the SSR either FWIW!

 

[Tom]

Fair enough.

 

[DavyCrocket]

Put simply the "Tube" lines tend to have less junctions in central London so the signalling system can see further away.

Some places don't have them at all as there is no TD (Train Desription) feed. Some of these are Edgware Road - Hammersmith via Ladbroke Grove and Acton Town - Uxbridge on the Piccadilly and anywhere north of Harrow-on-the-Hill on the Metropolitan.

At places like Paddington Praed Street (Circle line) the next train will only be shown once it is on the approach to that section of track (past a junction), as quite simple the signalling system does not know WHERE it is.
Between Wembley Park and Aldgate as the signalling is controlled by a computer it can see further and thus show more trains (except approaching Baker Street C&H e/b and Aldgate and Liverpool Street w/b)