These are the detailed schedules involved in a Train Merge. On the left you see the schedules of the incoming trains, on the right the resulting outgoing train. Please note how the schedules reference each other. Also note, that the length entry of the referenced schedule in the incoming schedules refers to the length of the first “real” leg (section) of the outgoing schedule. The length of the incoming trains is 75 m for both, so the result of the merge is 150 m, so in the merged schedule you can see how the lengths of the incoming trains add up to the length of the outgoing train.
The order in which the incoming trains are listed in the outgoing schedule is important. It indicates in which order the train parts needs to be assembled for the new train. The first train will always the front part, with the following sections following the head, until the last trains which builds the tail of the the new train.: The first leg there indicates that the train is heading to the right, the head being the one from “OM 9228#” and the tail originally from “OK1358”. That means, using a dead-end track OK1358 needs to go there first, after which you can send OM9228# as a switch movement to be coupled to OK1358 waiting there. If you look at the incoming schedules, you see that OK1358 is scheduled to travel before OM9228# – see stop time at Copenhagen Main. If for some reason OM9228# arrives before OK1358, you have to place OM9228# somewhere on the side until OK1358 arrives so that you can begin the merge operation. Don’t put OM9228# first on the merge station. Doing so will start the merge transition, and wait until OK1358 gets there, which can never happen since OK1358 is supposed to get in front of OM9228#, which is not possible if the waiting track is a dead-end track.
Remember, that the merge operation starts with the train that arrives first at the station – it does not matter which train arrives first. The order important for a successful merge is the order as listed in the schedule, not the order what time the trains may arrive.