My city bound train approached the first set of points outside Box Hill, stopped, reversed, stopped at the signal adjacent where the temp station is going, waited, and continued going forwards again.

At Box Hill, we were in the middle platform (as normal for an express service), and the stopping all stations train in the left platform was waiting for us. After Box Hill, we shifted to the left track and continued in the left track until just before Camberwell.

I speculated that there was some problem with the middle track (although I didn’t see any trains on it, they may have already cleared at the time though), and train control couldn’t change the points after Box Hill because we were too close, hence the reason my train reversed. In hindsight this doesn’t appear to be an accurate explanation.

Kind of unusual, it has been years since I last was on a train that unexpectedly went backwords (in the past this has happened due to overshooting the station platform).