I'm bravely going to do a train cake for DS for his birthday, does it really matter what the actual cake is? I'm going to do it in loaf tins but I think I then need to freeze the cake for a bit so it doesn't crumble when I cut it. I usually just bake bog standard lemon but I'm not sure that will go with buttercream icing? Will a basic sponge cake be okay in a loaf tin? 