Signal 73 - Is this actually how it goes?

Comprehensive approach locking - IE where the interlocking will “look back” to check whether a train is approaching is complex (and expensive) to provide; so in many schemes it is just omitted.

ME73 has a high approach speed and low speed pointwork just beyond. It’s also normally controlled by ARS so theoretically wouldn’t be setting the “wrong” route in normal operation; only when the signaller was running thing manually and made a mistake / something happened.

So yes, 240s non-comprehensive approach locking seems entirely sensible here.

Comprehensive approach locking - IE where the interlocking will “look back” to check whether a train is approaching is complex (and expensive) to provide; so in many schemes it is just omitted.

ME73 has a high approach speed and low speed pointwork just beyond. It’s also normally controlled by ARS so theoretically wouldn’t be setting the “wrong” route in normal operation; only when the signaller was running thing manually and made a mistake / something happened.

So yes, 240s non-comprehensive approach locking seems entirely sensible here.

Also, to follow up, the issues came about during an ARS test. It would appear that the trains stopping at South Ruislip did not have a proper setdown period written, so the ARS would set the route accordingly based on the schedule. This would then cause interference between a stopped train at South Ruislip and an express passing thru South Ruislip.

The same occurs over at West Ruislip on the Up Main. Train will pull into P4 to allow an express train to pass, however, if that stopping train does not have a proper setdown period programmed, the ARS seemingly plots a route immediately infront of the express train.

Newhampshires in post 142133 said:

Also, to follow up, the issues came about during an ARS test. It would appear that the trains stopping at South Ruislip did not have a proper setdown period written, so the ARS would set the route accordingly based on the schedule. This would then cause interference between a stopped train at South Ruislip and an express passing thru South Ruislip.

The same occurs over at West Ruislip on the Up Main. Train will pull into P4 to allow an express train to pass, however, if that stopping train does not have a proper setdown period programmed, the ARS seemingly plots a route immediately infront of the express train.

ARS is based on mathematics and predictions so the more information you give it, the better it can regulate. If you leave out an arrival time for a train that dwells for a few minutes then yes, the calculations are likely to be adversely affected.