If the WCML north of Wigan can provide the extra capacity that would be an option. The question then arises as to whether the Tuebrook Huyton section can handle extra traffic once the biomass traffic starts to ramp up as other power frames at Drax come on line? - assuming they are converted from coal? Three frame conversions are completed or underway but there has been little said about the remaining three. When the initial study was done the southern route via the CLC was seen to be the only feasible option albeit with its orbital crossing radial routes baggage. I am unaware as to whether the WCML north of Wigan was considered - but if it was it must have rejected at some point and if so I can only think that WCML capacity on the approach to Preston at Euxton was a constraint.
Not only was I suggesting reinstating the northern chord - I was also suggesting redoubling Ormskirk to Farrington - to prevent delays on the extant single track section bleeding over into the northern end of the Merseytravel.The alignment at Farrington Junction between the West Lancs and the Blackburn line so far remains unencumbered. Relaying the missing chord would need to undertaken as part of the overall rebuild of the line.
This is yet another variant of the "pig in the python" problem that arises when over rationalised systems are expected to ramp up capacity.
Knowing how long it takes in England to get DfT approval for even the simplest and most economical rail improvements, it looks as if we are stuck with the network as it stands for the next decade, and big engineering solutions for the Drax flow are unlikely.
The Huyton - St Helens - Wigan NW - Euxton jc - Farington Jc - Blackburn- Rose Grove - Copy Pit (Cliviger Gorge) - Hebden Bridge - Healey Mills - Wakefield Kirkgate - Knottingley route looks reasonable. The gradient up to Copy Pit is 1 in 65, compared with 1 in 59 and 1 in 47 up from Man Victoria to Miles Platting. From Edge hill to Huyton is pretty gentle, and I doubt if there are any steep sections via Prescot to St Helens.
The WCML north of Wigan has two Virgin expresses per hour, each way, a Manchester Airport to Scotland service each way, and the Liverpool - St Helens - Preston hourly stopper. North of Euxton Jc where the Bolton and Chorley line comes in, you already have four tracks. The Whelley loop used to act as the freight lines avoiding Wigan North Western, but it is long gone.
Just looking at RTT for Euxton Balshaw Lane, some hours there are two freights, others five or six. Would seem to suggest that a lot more freight workings could be fitted in. Between Todmorden and Milner Royd Jc you'd have to thread between the Calder Valley passenger traffic, and Transpennine services between Heaton Lodge Jc and Ravensthorpe, but nothing like the problems around Stockport or Manchester centre.
One just wonders if the tunnels and curves around Cornholme and Mytholmroyd are able to take the big Drax biomass containers?