These little tools will make a big difference to how many coaches or wagons your loco can pull. – They smooth the (usually) imperfect coning of the axle bearings in trucks/bogies greatly lowering friction. Two types, one with centre roller for standard freight bogies/trucks, and one with twin finger-rollers for bogies/trucks with a centre bolster for couplers. A low cost tool with huge benefits to those who care about performance!
Suitable for all N scale and many 009 models.