When attempting to be a clever dick and employ a slip at the exit to a goods yard do not ...
Bung it down more or less where it's supposed to go. ... fail to check that the slip is properly aligned and not reversed as to how it should be. ... fail to check it before fixing track to it. ... fail to check it before pinning it in place. ... fail to check it before mounting two points motors to it. ... leave it for around 2 months before having a proper look at it. ... have your wife nearby when finally noting your error and remarking loudly to one and all about the ancestry of a certain track manufacture.
The last one being particularly important!
At least I hadn't ballasted it. :-(