I've noticed in the past that, in the US, it seems to be more common to run what are clearly stock positioning moves in the counter-peak direction - often running non-stop and missing quite big stations on its way. An example can be seen on MBTA's Franklin Line in the Boston area, where the first morning outbound service at 3am calls at very few stations with a calling pattern not replicated elsewhere. I doubt that the service is well used in itself, and it's probably the return working that is its raison d'être.
It doesn't seem to be quite as common in the UK - a stock positioning move at 03:30am would almost certainly be an ECS, surely!
It doesn't seem to be quite as common in the UK - a stock positioning move at 03:30am would almost certainly be an ECS, surely!