The external load resistor is a bank of high power resistances for charging locomotive traction generators up to 3000 Kw, meaning slightly more than 4000 Hp. This facility is one of just a few of this power magnitude that exist in Spain.

For diesel-electric locomotives, it is possible to call up the diesel engine and the generator which carries up to 100% of its power over a bank of resistances that are used as the electrical charge in the generator terminals.

The physical dimensions of a bank that is used to dissipate up to 3000 kW of power require forced ventilation and a small building to contain them.

The configuration of the 30 kW bank comprises four interconnected resistance modules to obtain a final value of 0.5 Ω and 3000 kW, cooled by forced ventilation.

With this resource, one of very few that currently exist in Spain, Erion Mantenimiento Ferroviario can conduct all kinds of tests on locomotives at any power level that is required by keeping the diesel engine charged.