Windsor Line pathing

[Sad Sprinter]

I notice that regularly Windsor Line trains seem to, for no obvious reason at all, get switched from the slow lines to the fast lines before Clapham Junction at the last moment. Is there any reason for this? Most of the time there isn't any congestion on the slows and all that means is people at Wandsworth Town and Putney waiting for the train have to quickly hobble over to the fast platforms to catch their Weybridge/Hounslow train

 

[swr444]

I notice that regularly Windsor Line trains seem to, for no obvious reason at all, get switched from the slow lines to the fast lines before Clapham Junction at the last moment. Is there any reason for this? Most of the time there isn't any congestion on the slows and all that means is people at Wandsworth Town and Putney waiting for the train have to quickly hobble over to the fast platforms to catch their Weybridge/Hounslow train

NR usually do line blocks in the off peak on the lines between queenstown road and barnes, which usually cause the last minute platform changes. Some services are booked onto the opposite platform its meant to come in, even then the signaller can change it last minute due to the reason above. Sometimes it happens for no apparent reason though.

 

[Sad Sprinter]

Line blocks? What are they and why is that?

Sometimes it happens for no apparent reason though.

Do you mean to say the signaller can change the path simply because he...feels like it?

 

[swr444]

Line blocks? What are they and why is that?

Do you mean to say the signaller can change the path simply because he...feels like it?

It’s where network rail puts a block on a line to do stuff like safety inspections.

 

[Big Jumby 74]

Do you mean to say the signaller can change the path simply because he...feels like it

Signallers don't 'play trains' just for the sake of it. At many places, ie: Waterloo, and parts of the running lines, there are 'patrolling possession' blocks, which can mean a change to the normal pattern of train routing. These are planned in to the timetable. They are designed for the reason the name suggests, patrolling (and inspection) of that part of line or platform line. On casual observation of changing train routing, this may appear to be for no reason, but these 'time' windows are planned to allow the engineers access at certain times without having to pre plan for same, weeks or days in advance.
Also, as swr444 says, there are often more random safety inspections, which can take place at very short notice, possibly as a result of a driver reporting a rough ride at a certain spot, just as one example.