Can two trains be ran on one transformer and if so what size (watt) is recommended?
Do you mean independantly? Unles the transformer is multitap, no.
The power consumption depends on th etype of locomotives (open frame vrs can motors and then the number of cars or electrical lights (passenger cars). A typical toy train would pull about 30-50 watts.
Your larger transformers of yesterday (ZW, Z, KW) and the modern era (Z-400, ZW, MRC Dual, MW) can all run two trains (MW) or more (the rest listed).
You simply connect your track loops as dictated by the type of transformer used.
Ken
I just ran two complete passenger sets with a CW-80 transformer.
-Polar Express w/ 4 lighted cars on an inside Fastrack figure 8 powered by the A-U terminal.
-1935 American Flyer steam & 4 lighted coaches on the outer Fastrack loop powered by the programmable B-U terminals.
Nary a hiccup - it was a nice set up & everything ran great.
Rob
I have two Type Vs, 150 watts. I run one train on one, and two with the others. acessories, lights are split between the two.
I often run two trains off one transformer. I usually use new modern (100W) transformers and modern trains. I insulate the center rail on a portion of the circuit and then just add an on-off switch between the transformer hot and center rail of the insulated section. The engines need to be close in speed. I lock the (very slightly) faster one in forward. Then if it gets to close to the second I flip the switch and make it wait. It is more fun than just watching two go around. You have to balance the on/off times of the faster train. There are tons of other ways to do this as well.
Of course if you have command controlled trains and controllers then you do not even need the switch.
Jim H
I’ve run two trolleys off an 80 watt transformer. One usually catches up somewhat to the other - but doesn’t actually push it. At least in the city, they usually ran fairly bunched.