Why is the back of the wheels better than axle wipers?
The one on the back of the wheel will create more rolling resistance than an axle-wiper. A wheel wiper will probably also wear out quicker (the distance the wheel wiper travels is much greater per wheel revolution than an equivalent axle wiper). Axle wipers also create less friction (rolling resistance).
The only advantage is for when only one wheel is insulated and the other wheel and axle are connected electrically. Then a wheel wiper is needed for the insulated wheel.
Exactly... because unless the truck has Kato style wheelsets, you have to ride on the wheels to get all-wheel pickup.
And even if it does have Kato caboose/tender wheelsets(which you can still buy), it might be very tricky
to join the two halves through a plastic tube and still have some metal axle on each end exposed enough
to ride a wiper.
And because, according to my personal preference, as long as the wheels still roll, I would gladly trade some extra
rolling friction for large surfaces touching between the wiper and the wheel, so I'm hoping those larger surfaces riding on the backs might work better than an axle wiper.
Remember, this is for those pain-in-the-neck cases where we don't have all-wheel tender trucks.
