Good your back in the chair Jim!
The blue Vortoc fencing does a good job of forming a physical barrier from a live running line where protecting staff is concerned but they probably used the train as a barrier because of the 360 road rail machines swinging about.
We now have what's known as ALO rules to adhere to (Adjacent line open) and they are pretty strict on what you can and cant do near an open line now, especially so when it comes to on track plant in use.
Without the train there as a barrier, they wouldn't have been able to do the job, its that tight now where the rules are concerned!