But it does strike me as odd that Fairwood Junction to Clink Road Junction isn't four-tracked. It's only a couple of miles with pretty much nothing in the way, and the two-track section there just introduces needless opportunities for things to go wrong.
There are of the order of 4 trains each way per hour through that stretch and noting there are layby tracks at both Frome and Westbury, the issue of slow trains and fast trains mixed eating up lots of paths is much less than elsewhere. If the Bristol Metro were be to extended to Frome you would be adding an extra train each way, ditto if that were in combination with turning the Heart of Wessex to Hourly as far as Yeovil Pen Mill. To some extent, those extras would replace the
SWR» fillers between Yeovil and Westbury. I suspect that 4 tracking between Swindon and Didcot, or between Didcot and Oxford, would have a better case, and that redoubling Chippenham to Trowbridge would also be a better investment.
Interestingly, the Westbury to Frome corridor along the railway looks bland on a map ... but there's history there. A relief road just to the north of the railway, linking the A36 to the West Wilts Industrial Estate would move (road) traffic from the South Coast to the industrial area - and through traffic headed further north too - away from the pinch points of Haynes Road and West End in Westbury, which have congestion, vibration and air quality issues.
