There are ten minerals in Mohs scale: talc, gypsum, calcite, fluorite, apatite, feldspar, quartz, topaz, corundum and diamond.
Would it be useful for us to described how damaging the effect of a change from plan for trains is using the Mohs scale - for example, this morning here is an example of
Talc - a train on which a reduction from 3 cars to 2 isn't going to be any sort of problem, and it still makes all of its calls at the planned time.
08:22 Westbury to Swindon due 09:07
Facilities on the 08:22 Westbury to Swindon due 09:07.
This is due to more trains than usual needing repairs at the same time.
Will be formed of 2 coaches instead of 3.
An example of
Diamond - should be very rare - is a meltdown such that passengers cannot make their journey to arrive within 3 hours of when they had planned, alternative replacement transport not provided.