How do I turn on a GP40-2?

[Union Pacific 4-8-2 Mountain]

In one of the Battle For Sherman Hill Scenarios Specifically the MOW west one, It tells me to start the locomotives however even though I pressed the button that would start locomotives (which I think is the button that looks like a Key in green, the engine won't start. Am I doing something wrong?

[Rocket Witch]

...\Steam\steamapps\common\RailWorks\Manuals\EN\DTG - GP40-2 Loco Pack Manual EN.pdf

2.2 Cold & Dark Start Procedure
1. Move the Engine Run, Generator Field and Control & Fuel Pump switches to the on
position (Up).
2. Turn the Engine Run Isolation Switch to the Start/Stop Isolate position.
3. Depress the Engine Start Button until the engine has started.
4. Turn the Engine Run Isolation Switch to the Run position.