Missions With 8 Carriages Cannot Be Completed

I have a problem with the mission in scenario 1, a freight shunting locomotive , where I have to attach 8 carriages and get them to a specific point. The problem is that you can't get started with these wagons! Resetting the game and console doesn't help. I play Xbox one X. Help

 

On which route?

 

which route? which scenario?
No one can help if you don't give any information

 

I've found that this sort of problem is related to the brakes. Specifying the route and scenario will make it easier to help you. However, if you have to couple to rolling stock and then move it, it maybe the case that the brakes are on the wrong setting. For example, some of the older UK locos there is a brake selector which allows you to select either air or vacum brakes for freight or passengers. Certain rolling stock will only work with a certain brake setting.