I have successfully replaced the TLC (tension lock couplings) on two rakes of MM mk2 coaches. The first rake was done with kadee and the second rake with Hornby R8220 close couplings between the coaches but a single kadee at each end of the rake for coupling to locos and better visual appearance. This works with fixed rake formations.
Height is perfect when the kadee no 19 or 20 are glued to the underside of the NEM pocket rather than in the pocket.
The Hornby R8220s (below) were fairly easy to fit once the TLCs were easily removed from the mk2's using the scalpel to trim the ends as in the first photo above. The last coach at each end of the rake had a kadee no 19 glued to the underside of the NEM pocket for coupling to locos. Spent a while doing running trials with the close couplers with reasonable results so far except for one coach which occasionally suffers a lock of the NEM coupling plate causing a derailment. I should be able to tweak that tomorrow in daylight when I can see watch is catching on the chassis.
Comparison below of Hornby R8220 close couplers and the kadee's below. The orange roof rake have kadee's and the black roof have the Hornby R8220 close couplers. When stationary both types offer identical close coupling qualities, however once running a small gap will open up with the kadees, but nowhere near as big a gap as the standard TLCs that come with MM coaches. The Hornby R8220 close couplers keep the gap closed except on curves when the gap between the coaches opens up proportionally with the radius of the curve which avoids buffer lock and derailment.
Stock coupled with either the kadee or R8220 can be lifted vertically out of a rake unlike TLCs (tension lock couplings), the kadees are the easiest to uncouple and lift out.
PS: NEM 362 pockets as a standard seem a joke. None of the coaching or wagon rolling stock I have bought from any Irish vendors have the pockets at the correct height and in some cases not even the correct horizontal position relative to the buffers and in one case the NEM pockets were not even the correct length. Same problem seems to apply to many British outline stock.
Edited by NoelG, 16 April 2018 - 09:06 .