couplers

[sgtallen]

I recently purchased some rolling stock that has the old school square hook couplers my question is how hard would it be to up grade them to the newer magnetic couplers

[Maletrain]

There are conversions to MicroTrains magnetic couplers that use the same coupler box as the old style ("Rapido") couplers that you have now.  They have a different configuration inside the box than the regular MicroTrains couplers, and often do not work as well as the regular MicroTrains couplers because the configuration inside the box tends to let them sag outside the box.  But, it is the easiest conversion, especially if the couplers are mounted on the trucks instead of the car bodies.

It is also possible to remove the box and replace it with magnetic knuckle couplers and boxes from MicroTrains and other manufacturers.  That is somewhat harder, especially if you are talking about truck mounted rather than body mounted couplers.

The easiest way to replace truck mounted Rapido couplers is to get new trucks with magnetic knuckle couplers mounted on them, but that is also the most expensive approach.