Riding on a South Western Railway British Rail Class 444 EMU Siemens Desiro 

This was a train from Woking to London Waterloo.
This was my first time riding on board a Siemens Desiro Class 444 Electric Multiple Unit in over a decade. The difference between Classes 444 and 450 is that the former has 1 large pneumatically operated sliding door per opening while the latter has 2 smaller ones in opposing directions. They're all plug doors.
Typically, Class 444 units are used on longer journeys. Having said that, the train operator South Western Railway often couples both types together as they are compatible.
The trains are made by Siemens. They're powered by 750 Volts 3rd rail.