From a purely engineering POV, the LR55 rail does seem promising, which is why I am surprised that none was used for the recent Blackpool system upgrade.
Tram systems in this country are hampered by the legislative requirement for the tram system owners to divert utilities at cost to the scheme when using the "traditional" construction method, which I beleive is not the case on the continent. The LR55 seems to avoid this by utilising the existing pavement structure.
While this is all very well, it relies on the existing pavement having enough residual life in them in the first place, which for the majority of roads isn't the case. On the flip side, resurfacing would be much easier, because there isnt a slab to deal with.
Im on the fence with this one. While I think Preston would benefit from a light rail system, it would only be of benefit in a more expanded Lancashire-wide light rail system. I think rather than pushing for a completely new system in Preston, perhaps they should use an existing system to expand upon, to properly prove the concept.