Steam Don't Have Time To Set Up Train?

In the West Cornwall Local DLC, if I start a Timetable service, it doesn't give me time to set up the safety systems.

The simulation would come in at say 0552:11 and I need to depart from Penzance at 0552:30.

Also even I don't set up my safety systems I still can't depart on time because I need to insert the Master key to on, put the reverser into Forward then open that doors, it takes at least a minute to load the train.

It's impossible. Plus I can't make up the time back up.

Not only is it Penzance to St. Austell it's also St.Ives branch to St.Erth.

Can someone please see if they start the timetable 2 minutes earlier.

 

I can't try this right now, but can you spawn on foot a few minutes early and take over the train with enough time to set it up?
For the example you gave, you could try Timetable > On foot > Penzance @ 5:50am and see if you have sufficient time to take over and set up.

 

I went into on foot but it was a random train in the platform.

It wasn't the train I wanted to drive I wanted to drive the class 150 but the train in the platform was a mail train with a class 47.

 

As far as I know, trains are substituted on the same service if you own other DLCs with diesel power. For example, the 101 will sub for the 150 if you own NTP or GWE. NTP can also bring Class 45/1 and Class 47/4, and if you own that DLC, you can also get Class 40.
First, make sure that the train you see is running the exact same service you wanted: board the locomotive, sit in the driver seat and check the service number when you're asked if you want to take over.
If it's not the right number, check that there are other trains around, or incoming to your station (in case you are very early for your service).
If it is the right number, try to restart and see if the train changes.