Nitram2
Hello & Welcome to the Forum!
Also
Welcome to the sometimes confusing world  large scale trains.
Your potential train is a "G" scale train that operates on 45 mm track.
Track is available from various producers in brass, stainless steel or aluminum.
Plastic track is also available but not applicable unless you convert over to R/C & onboard batteries.
Both new and used track are readily available, with used brass .332  track in. the 3 to 5 dollar per foot range.
As to the power supply, it will depend upon the amount of track you plan to power.
For my small 8 X 14 loop l use a 1 amp power supply. 
For the several hundred feet of track in rhe big layout l have a 10 amp power supply.
All my track is .332 brass, mixed, new and used.

Happy Rails!
dave