Is there a supplier for the drive belts that are used in older locomotives such as Varney? Thanks. 
Not sure if these are still available, but a potential alternative would be to try stationary/office supply stores for suitably-sized rubber bands. I’ve got an old VCR that’s using rubber bands in place of the now-unobtainable drive belt, so the idea should work as long as you can get the right size bands
I am using silcone bands sold in the cosmetics area for pony tails and braiding hair.
These, like rubberbands will dry rot after awhile.
Thin neoprene O-rings will work on locos with pulleys. I’ve tried them on Athearn locos ,but there isn’t enough surface area to grip the upper driveshaft.
Thanks for the info. Will keep looking and experimenting. [:)]
Found a 7/8" rubber band at my local office supply store that seems to work. They are made by Universal and it is a size eight. Comes in a 1/4 pound box so should last awhile.
Now to see how long the bands last. They seem to break in quickly and a smooth operation results.
They should last a while. Rubber bands tend to dry out if left unused for a long time, so consider putting the spares in an airtight bag or box to keep them fresh.
Thanksfor the tip Railroading_Brit. I appreciate it. [:)]