Could be possible to make a button to autoconvert....

[Teddy]

I was thinking, when you get a lot of trains, and got Monorails, then you use the tool to become the electric rails into mono ones. But it takes so long to build every train...

Could be something done about it? like when converting from rail to electric, but to make it usefull foward, to make electric to mono and mono to manglev?

[cmoiromain]

Using the search function would have given you the dozens of threads about this. Many people agree with you, but the devs don't. The way to do this is to use cloned trains, so replacing them one by one is not as long (count the number of trains in a group, and create just as much).