I have posted some pix of the 660 crane and uncataloged 1684 set it came with c. 1941. The crane has manual/low-hood couplers, trucks attached with hollow eyelets. Note that 2660 has been factory painted over, so no number shows. I have had this set, 1684, 1689T, 1677, 1677, 660 (or maybe 1660), 1682 since purchased at a Chicago area meet in the 1980's. Also, since the 2660 door has been opened (we watch too much Perry Mason), I am showing pictures of a 2660 crane made during WWII by Madison Hardware. The crane is normal late production, except it is mounted to a 1600 series frame, which Madison apparently had a large stock of.