Hi z-scalers, while I changed to AZL regarding locomotives I am thinking about conversion of my powered MTL F7-A unit to a dummy for use in MU-service. But with the original bearings the trucks don't run easily enough. I could not find out, if unpowered B-units have other type of trucks, and spare parts are difficult to obtain in Germany. So, does anyone have experience for a modification with the original A-unit? Steffen
Unusual for the bearings to make that much difference. Are you sure there are no wipers making the electrical connections? Are you sure the difference is not the friction of the bearings, but the extra weight that locomotives have to have, as compared to other rolling stock?
They are IDENTICAL, although there are no wheel wipers in the B. There is a tread on the American Z Lines (AZL) for about this from David @ tjdreams. http://www.azlforum.com/thread/603/micro-trains-f7-units (you will need to register) They do not roll easy and everyone has had their input or method to improve them. Fortunately, the A unit pulls so well that it makes up for most of it.
The bearings are THE reason the MTL F7 has this problem. The trucks just have bearing journals, much like an engine block. The alxe shafts sit in the journals and there is a lot of surface area in contact. Needle point bearings like most everyone else uses only have a small point in contact, therfore much less rolling friction. Different trucks are the only solution that I could see and I don't know of anything that would fit. As for the wipers, they are in the frame and contact the truck gear towers and are therefore no present in the B unit . It only has a flat plate to attach the trucks. They pull like mad, but are very noisy and need a lot af maintenance to keep them clean. Disassembly and reassembly can be very finiky. They look good until you put them side by side with AZL locos, but there is about 40 years difference in design. Anyway, they are entirely workable, but mine lean to one side or another, and are a general pain to deal with. I am constantly being enticed by the new MTL F7's coming out, but I don't think it is money well spent for myself. Check out that forum link, much info there. Trey
Hi, thanks for your answers, it seems, there is no simple solution. Hm...thinking about removing the inner contact areas of wheels and new axles running in plastic bearings, would be just another project. Regards, Steffen
