There's a huge variety. Grinding trains usually travel at around 15-30km/h (depending on what model of grinder, how badly the rails need to be ground) and it looks like what Hollywood thinks an emergency brake application looks like
They usually have a water tender at the end with a water cannon to spray down fires started by the grinding train itself.
Railway ballast cleaning to remove fines and tamp
This level of cleaning is expensive... Normal freight lines don't need this level of replacement except maybe every 10-20 years. But they do need their ballast tamped every so often to make sure you compact voids and re-lock ballast together.