Said it many times before and there is a glimmer of light with the 64 bit upgrade. What TS really really really needs is the ability to select any loco anywhere whilst in freeroam, so you can really run layout style....really 'freeroam.' Currently you're 'tethered' or limited to selecting locos within line of sight or the boundary of the one you're in.
You'll always be limited by the scope of the route you're on, so "free roam" is always going to be constricting
You can. Start anywhere on any route and drive the train you want anywhere along the line - if you spot a different train you just stop - click on that train an drive it where you want. Jump on a train at Kings Cross and do you drive a HST or a Class 91 or that Austrian Loco in the other platform. Or you can move along the line in View 8 to a different location to pick another train Free Roam is only limited by what trains you have on the Layout - like a Model Railway. The only restriction is if a train has been placed but there is not a Driver Icon on the Loco/Unit - that is easy to change in the world editor Peter
If you just load up a freeroam without clicking on a train, have you ever noticed how you can fly wherever you want? As soon as you click a train, you are confined to a mile-and-a-half (I think) radius. If you want to drive anything outside of that, you need to drive there yourself. A bit annoying on a single track branch where there's no good place to store tons and tons of trains, as I'm sure Broomwagon does all the time
Instead of just having a few trains in one location go in to the editor and put them where you want along the route. You could even start off with an Electric loco and at some point take it off the train and pick a diesel you have parked nearby.