Back to the trains,
In another forum I read that the crossover and slip on the Seaford Main leading to storage road #2 was taken out because the 4000s couldn't negotiate it. One correspondent said 4000s could only use platforms 1-3; haven't proof of this, others may know.
Signs have appeared on the Seaford and Belair Mains saying EMUs noaccess to Plat 5. This would imply 4 is accessible. Also it has been wired.
The removed crossover/slip didn't appear to differ in geometry form the rest of the station approach. As they were removed months before 4000s reached ARS, I suspect it is more likely that the removal was done to simplify the overhead installation. Since the storage road is now only accessible from Plat 1, its usefulness is limited and possibly explains why it was electrified.
I noticed today that there are signs at Mile End banning EMUs from the crossovers, surprising since they have been electrified!