Alternative Linear Mechanism

I would sugget using rollers on the inside of two C-channel runway. Your devise would have a trolley motion inside of the channels. Leaving a gap between the channels allows for your moving mechanism to be attached to the trolley. You can control perpendicular motion by installing guide rollers that fit between the gaps, two in front and two in back that are attached to the trolley. As far as linear motion and where your devise needs to be stopped, that requires more detail. The mass that you are moving, what power source are you using to move the mechanism, both need to be considered. I hope this helps!

In the same way of thinking, I remembered that tracks made like a trelice with three tubes, 2 tubes being the car support and one being the support for the other two. This arrangement gives multi-direction support with two tracks. A good arrangement if track rigidity is a must, because you can improve it by placing the tubes and building a 3D trelice, light and stiff.

If you need just vertical suport and linear movement, I've seen a good example on a train leading to the Corcovado mount in Rio de Janeiro. It's a conventional track, with linear gears to push the train uphill. In Santiago de CHile, I've seen something similar, but with steel cables doing the job.

Long travel means very different things in different situations! in the machines that I design, long travel means over about 10 cm, whereas the funicular elevators or trains mentioned by the person from Brazil may travel many km, like the one that used to cross the Andes near Mt. Aconcagua.

You also make no mention of the positional accuracy required: If you are moving laser optics for precision cutting, you need to maintain both longitudinal and transverse position within a few thousandths of an inch (hundredths of a mm) or better over the entire range of travel, while a funicular elevator only needs to have positional accuracy at the stopping points. Precision costs money, but an appropriate amount is a necessity!

Give us some details!