Adding A Missing Marker To A Platform On A Track That Has A Proper Marker

I'm trying to add a missing marker on a platform which has disappeared for unknown reasons, leading my AI train to drive in reverse and collide with another AI train later down a portion of the track that has a marker. How can I do that in the scenario editor?

 

Watch this from around 5min 30 and it shows how to place and use a track marker.

You need to do it in the Route editor instead of the Scenario editor
The train going the wrong way might be down to track directionality or Track Type

 

The problem is that my track (platform) marker doesn't allow me to stretch it across the entire length of the platform for some odd reason..

 

Are there any points in the platform?
Can you post a picture?

 

Sometimes in can be a bit awkward to do. Try zigzagging the mouse a little while LMB pressed.

 

I asked it he could post a picture so we could see - 4 days ago