Trouble is the top track has be clear of the bottom one to allow a train to pass underneath. You need at least 2 inches and no matter what you use there isn't much length to rise that much.
It will arrive, waiting excitedly for it won't speed it up, much like waiting for a kettle to boil. Now take a deep breath and relax. 😉 Must be a nightmare at your house approaching Christmas. How many sleeps till Father Xmas comes? 😆
Keihtp look at my picture above. Uncoupling never fails and unless you are using a huge spatula how the heck can it derail a wagon? 🤔 This is a reconstruction of an uncoupling posed by models. No wagons were hurt taking the picture.
Slough had a lot of 61XX locos. I reckon the cement wagons were ferried to PR with small locos and once the train was made up a larger loco pulled them to their destination.
Two of the OP's four posts are whinges about Hornby. Seems to have given up as he didn't get the response he expected from us. 10 Class you say the model you saw did have the linkage so perhaps his had come adrift and was loose in the box.
I agree LC. With fencing I put plenty of PVA down and stand the fence in it. Usually does the trick. Might need holding in place temporarily until it sets.