I thought I may have seen a bit more than this?
Apart from the trunk intermodal routes (WCML, Birmingham to Southampton, etc),
or busy coal areas (Barnetby, Doncaster, York, Knottinghangley, etc.), you
can't just "turn up" somewhere and expect to see a procession of freights!
Routes which don't have a lot of coal/intermodal/other regular freight traffic,
such as the line through Cheltenham need to be visited at particular times,
and/or on particular days to avoid disappointment...
...which is why Cheltenham (and Gloucester) features as a Freightmaster timetable;
the cost of a subscription can very quickly be recouped in train fares/petrol
which would otherwise have been wasted visiting on the 'wrong' days/times.
So when people tell me that they "can't justify the cost of subscribing to Freightmaster",
sometimes that turns out to be a false economy, especially when the cost of
an annual subscription is about the same as a tank of petrol/diesel these days!
MARK