What is the problem re-opening the line is intended to solve?
That may focus minds on what the priorities should be - end to end journey time, commuter access to Leicester, through access to the rest of the National Rail network etc?
A standalone light rail concept system may not be appropriate in this instance but in principle could reduce some of the capex to upgrade/facilitate sharper radii curves etc and certainly opex (lower staff costs, simpler signalling including line-of sight) but may be tricky with the residual existing freight services, severe gradients for battery-powered or diesel trams and have few synergies of being part of 'the railway'. Either way these kind of potential re-openings may call for some slightly different thinking to get a positive business case to get them off the ground - re-opening something 'as was' which was built to carry freight won't necessarily be a reasonable value for money solution to today's passenger transport problems.