Out of the box the new Hornby APT Non-Driving Motors will not connect together. The NDM Sc49003 from the R3873 APT 5-Car pack and NDM Sc49004 R3948 which can be purchased separately would not connect together. There is nothing in the service sheet about it. It looks like the R3948 was assembled incorrectly. This video shows the problem and how to fix it. I checked both R3948 models that I had, and they both have the same problem.