All goods types and passengers wait on the specific platform assigned to that line that they want to take. If a train uses a different track and stops at the wrong platform it would not have anything enter or leave it? I like that one line doesnt have to wait for a train on another line cause they use different platforms.
Besides the Queue system in openttd where you would have 1-3 trains waiting for full load constant isnt profitable in train fever. Better to have as few trains that they instantly fills up when the come imo.