Digital Direct Couplers User Review
by Bill Nanney

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DDC Installation in a P2K SW8/900/600
Monday, August 11, 2003

First impressions of all the parts and soldering requirements were a little scary. In order to make this uncoupling system work requires a major amount of frame modifications and it appears to be very critical that these modifications be done with a fair amount of accuracy. Thus, I would recommend that any one requiring this type of uncoupling purchase the RTR frame form Tony’s Train Exchange. One was included in this kit and it did make assembly much quicker.

The first difficulty that I had was making sure I understood the directions clearly. More detailed diagrams of how the parts fit together would have definitely helped. I did print out the breakdown of the assembly from Tony’s web site and that certainly helped.

Installation of the electronics was straight forward and I had no issues. The only thing that must be stressed here is that the assembler has a good soldering iron with a needle point on it. Cutting the wires to the correct length and tinning each wire before attempting to solder in the small eyelets is an absolute must!!

The instructions recommended that putting the wires in the eyelets from the bottom and soldering on the top was the best method of soldering the wires. This is impossible if you follow the instructions for assembly. Everything is already in place before wiring is done.

It was not clear to me if the rear light was suppose to be put back in to the locomotive and if so where do you connect it to make it work. I know where to connect the lamp per the decoder instructions and the pictures of the finished shell showed the rear lamp holder installed but the instructions clearly said to remove all of that stuff but never said to re-install it. The locomotive has non-directional lighting and no rear lamp. I think that needs to be addressed. The alignment of the front LED with the headlight lens appears to be very poor. I will fix all of this but I am giving you my thoughts of the kit as received and installed per the instructions.

Mechanical assembly was actually pretty easy except for getting the push rod keeper on the push rod. My huge fingers did not work well here even with tweezers, etc. I ended up drilling the keepers out with a .0465" - #56 drill bit so that it would slip over the push rod. I also had to polish the ends of the push rod with 400 grit emery cloth to make the keeper slip over the area where the push rod had been cut from its wire stock.

After putting everything together with out the shell, everything worked perfectly. The coupler de-coupled every time. They also matched up with many different makes of rolling stock with no issues – Athearn – blue box and Genesis, IM, P2K and Walther’s.

The BUMPS on the SW coupler box openings of the shell which needed removing was not clear to me. When I looked at these openings, the only BUMPS I saw were the safety toe plates at the ends of the brakeman’s step on the coupler openings. After installing the shell and struggling to get it to snap in place, it was obvious that these toe plates had to be cut off. So I removed the shell and clipped these toe plate off and this allowed the coupler box to move more freely in the openings and allowed easier installation of the shell.

One change I made to the frame was countersink the guide pin hole in the rear of the frame as the original equipment frame was. I used a #50 drill bit and literally did nothing more that remove a couple of thousands of metal. This made for an easier shell assembly and seating of the rear tabs on the shell.

After installing the shell, the front coupler would not operate freely. It operated but was obviously hanging or binding on something. The rear coupler operated flawlessly.

I removed the shell and carefully inspected the radiator area of the shell to see what was causing the bind. There is a small protrusion on the front of the shell that was causing the pushrod to bind as it was moving outward and down. This protrusion is very small and is right next to the nose snap or spacer – I am not too sure what the large plastic thing in the front of the shell is for. Anyway, removing this plastic certainly solved all the binding issues.

Un-coupling is working perfectly. I have run it many times now in the switch yard with many different styles of rolling stock and have had no issues at all.

If switchyard operations are important to model railroaders, this is the way to go!!!! I loaded the couplers with 6 - ACF 70 ton Kato hoppers and 3 - 50 foot boxcars that meet NMRA weight standards. I pulled them up a 2.8% grade with no problems. It actually would uncouple up to three of the ACF 70 ton cars on that grade.

I coupled and uncoupled with Kadee #58’s, McHerry #51’s, Bachmann EZ Mate I’s and II’s and of course with other Kadee couplers. No problems with any of these.

Draw backs: – would not uncouple if the trucks were not perfectly straight. Any curvature at all in the track and the coupler box would bind on the trucks. I do not see this as a problem for me as my uncoupling is done on straight-a-ways. If I forgot to move the coupler back to the up position immediately after uncoupling and the locomotive traveled over a curved section of track, it jumped track. However, the locomotive never jumped track, even on a tight curve, as long as the couplers were in the up position.

Overall evaluation – VERY GOOD!!

I have included some photos for your review.

Thank you,
Bill Nanney

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