You can place AI trafffic in the path of the player train to generate red signals but being overtaken by an AI train is not possible.
The only way to achieve something that resembles what you suggest is to have an AI train running on a parrallel track (like the 4 track stretches into München) and giving that train same direction as you. If you then also have an AI train in front of the player train (which will cause red signals) you will
1-overtake the the AI train that is on the parrallel track
2-stop at the red signal generated by the AI train in front of the player train
3-now the AI train on the parrallel track will drive past you.
If you time it right this is possible. I’ve done it in my Real Drive scenarios and it makes the drive very realistic.