I've built more stuff but I didn't want to show it all before it's done!! It's not so good a screeni for you can't see so clearly the mouse and the phone!!!
I know It's almost nothing but I was trying to find how to make that screen a switchable texlight!!
Use a multi_manager to target more then one target!! Target this multi_manager with the button and with the multi_manager target the multisource and the doors!!(You must use only one object to target the multisource or else you will need to activte all the objects that targets the multisource. So if you want to make more then one object that will trigger the multisource but that you wont need to activte all of them use, make them target a trigger_relay that targets the multi_source)
Start off flag(if there is) or a trigger_auto, with the trigger state flag set to off, targeting the trains!! Use the doors to target the train agian so when they shall open the cargo will drop!!
Thanks helped to insert another detail in the map!!! Sorry I didn't knew it's going to be so complicated but once when I created a switchable texlight with those tnnl lights I didn't need all these stuff! :