A failing clutch on an EMD turbocharger will drive you crazy. It will puke black smoke, die or not even start (remember these are two stroke that must have positive crankcase pressure).

ALCO and GE turbos are not mechanically connected to their drivetrains, so are dependent on exhaust gas only to drive them.

An engine must have heat, fuel and air (oxygen) to work. If there is insufficient air in relation to fuel, you will get black smoke out the stack - or even flames in extreme cases. A normally aspirated four stroke engine can only generate so much horsepower. Adding a roots blower allows more air to support combustion in the cylinders and an increase in horsepower. This comes at a price as some of the engine's horsepower output must be used to drive the roots blower, and this amount can be substantial. As turbochargers became practical and reliable, most four-stroke engine builders dropped the roots blower in favor of turbochargers which were more efficient at high altitudes and did not require power to drive them.

To prevent excessive black smoke, the load on the engine and fuel must be limited until the turbo is up to speed providing sufficient air for combustion. To prevent excessive exhaust smoke due to turbo lag, various schemes have been used to limit the fuel injection until the turbo catches up. The simplest scheme I have seen was used by Cooper-Bessemer on their FWL-6T used on the GE 70/95 ton. There is a dashpot where an adjustable choke allows you to limit haow fast the governor can increase fuel.