Even though you have the heatsink, I would still recommend orienting your board with the heatsink facing up verses on its side. You definitely have the room for it in these locomotives. This will give you better heat dissipation (be sure to update the firmware to v 1.05 as well to reduce future liklihood of overheating). I would also recommend mounting the module up a bit higher. This helps a lot with communications range. You can fashion a little box out of styrene or balsa wood and set the mounting bracket on top of that. The locomotives I've mounted up higher have noticeably better range than the ones I mounted right to the chassis frame. If you leave the fan hooked up I'm curious if you will experience the same issues I did (as per the thread Greg pointed out). Per Tim Ring, with the v1.05 update we should not need fans. The heatsink should provide enough heat dissipation (again, per Tim). My experience on this is TBD as is has not been hot enough here for me to test this claim since the update came out.
