火車 = train, national rail
tram is light train (like HK's MTR) = they r in Croydon, London's docklands, Birmingham, Manchester, Sheffield, Newcastle, Nottingham and Blackpool.
tram website
http://www.thetrams.co.uk
National Rail =
http://www.nationalrail.co.uk/
they got internet ticket booking, train times n fares, stations n desitinations, Train companies n maps etc
Also you can check
http://www.tfl.gov.uk/ (informations of transport of london, incl bus, tram, rail, walking, etc)
u may need to take underground to some london national rail stations.
you can buy "london pass" incl 4 major public transports. you can go up to 55 zone inner or outer londer, up to 7 days.
http://www.londonpass.com/transport_zones.asp (incl street map, infomations n fares)
Railplus, UK train pass - rail networks of England, Scotland and Wales
price from $350 (4days adult) up to $1478 (first class, 1month adult pass)
http://www.railplus.com.au/passes/britrail_passes/britrail_consecutive/consecutive.cfm 