Probably massive problems!
If both powerbases put a carrier signal on then they will interfere with each other.
If Carrera digital works in a similar way to DCC, then the first powerbase will be sending signals made up of + voltage and - voltage, the - voltage will be cancelled out by the other power base
Depending on the circuitry and protection of the powerbase design, the bases may not like having power fed into them at their input, and hypothetically could be damaged
If both powerbases put a carrier signal on then they will interfere with each other.
If Carrera digital works in a similar way to DCC, then the first powerbase will be sending signals made up of + voltage and - voltage, the - voltage will be cancelled out by the other power base
Depending on the circuitry and protection of the powerbase design, the bases may not like having power fed into them at their input, and hypothetically could be damaged