I was just sitting at sidcup when a networker went through quickly without stopping. Out of curiosity I looked at where it was going on RTT. It was running empty from Slade Green Depot to Victoria, I then looked to see what service it then formed but it appeared to be another movement out of public service to Blackfriars, then back to Victoria, then the same return journey, then down to Beckenham Junction, then back to Blackfriars, whereupon I lost interest and stopped following its planned route on RTT. Im not a railway employee, so apologies if it’s an obvious question, but I was wondering why an empty train would make all these journeys? Training? Maintaining route knowledge?