Tried All The Class 43 Controls But Didn't Work

I have completed the tutorial for the class 43 on Train Sim World which was fine. But when I got on the services mode, I tried all the controls to start the engine but it didn't work. It has left me very frustrated. Can anyone please help me with any recommendations?

 

The engine is usually running to start with on service mode
So all you need to do is click the reverser master key to on and set the reverser to forward
Then release the brakes and apply throttle

 

The engines normally start once u walk onto the train

 

Once you board the drivers cab, you have to press several buttons to start.

 

Thank you so much. It worked after I completed a scenario!