Fair point - but my point still styands - how many trains per hour are there?
Last Sunday, according to Real Time Trains, there were 37 trains in 13 hours (2 freight 35 passenger):
(Melksham (Station code) - next trains)/2014/12/14/0000-2359?stp=WVS&show=all&order=wtt" target="_blank">http://www.realtimetrains.co.uk/search/advanced/MKM/2014/12/14/0000-2359?stp=WVS&show=all&order=wtt
But we shouldn't be scoping the future strategy based purely on current levels on a fast-growing line, and assuming that a lot of freight on diversion can be pushed through too.
To say (extra) freight would have negligible interaction with passenger services is wishful thinking at best, or is a plan based on ignoring or removing the passenger traffic at worst.