Using commercial off the shelf technology without proper testing and certification is absolutely cutting corners. See: Kaprun disaster.

I just read the wikipedia article; thanks for mentioning it.

I'm not sure it's a good example of your point, though. Notably:

the cause was the failure, overheating and ignition of a fan heater in the conductor's compartments which was not designed for use in a moving vehicle.

The onboard electric power, hydraulic braking systems, and fan heaters intended for domestic use increased the likelihood of fire.

The fan heater is the only off-the-shelf technology listed here, and there's no suggestion that it was part of the train's design. It seems likely that a train conductor brought it on board to keep the compartment warm through the workday. Still a bad idea in a train, especially on a 30° slope, but not an example of the designers cutting corners.

Edit:

Thanks to others for linking photos and a report (in German) that show how the heater was installed. It was clearly not a case of a conductor just setting the heater on the floor, but the installation still looks very much out of place. Perhaps corner-cutting was involved, but this doesn't look like something done by the train designers. Even an expensive industrial heater seems like it would be an extraordinarily bad idea in that location, right up against high-pressure hydraulic oil lines. Does someone have the details behind it? It looks more likely a (very foolish) modification made by someone else, like maybe the train operators.

For anyone else following this, those hydraulic oil lines that the heater was nearly touching were apparently pressurized at 190 bar, which I think is about 2700 pounds per square inch.