This power supply is quite limited. However it is fine for the loco of your starter set.
I burned mine very quickly as soon as I started to use it out of the basic circle, in fact I tried to power a USA trains GP38-2 having 2 trucks!
If you want to power two locos at the same time you will be close to max power or even higher. If you have two tracks that means 2 locos ?. If you use the second power pack from another starter set for sure no issue. With a single power pack your 2 locos will always run in the same direction.
I would recommend you to buy a 5Amp power pack to power your 2 tracks simultaneously.
This is what I did, I kept the small LGB transfo 32 W (LGB 51090) to power all my switches but I bought a more powerfull transfo (Piko 35000) suited with a 5Amp controller (Piko 35002)