Thanks for the photo Greg.

This looks identical to the system used on those old Tornados with IYE beams. A smaller line and some larger "wheels" (if you can fit them) would probably help. Our Marstrøm Tornado dont have ball bearings where the traveller line passes trough either, and we never missed them. However, the car itself is a poor design. We had a traveller like that on our first Tornado, and it was a pain in the a.. A good kick to get it started when we wanted to travel out was often needed if it was loaded up.
Even if you could replace the 'wheels' running on the track with needle bearings, I dont think it would work well.

If anybody have tips on how to make it work better, I would also be interested. I have a beam and car lying in storage which I could put to use and save some money.