Select Actions 
Assign Inbound Order. (For outbound trains, this is Assign Outbound Order)
When you adjust the order of railcars (on page 1) in a train list, the XPS client automatically updates the order attribute (depending on the train, Inbound Order or Outbound Order). Still, there may be some other railcars that are in the correct top-to-bottom sequence in the list, but with the wrong order number. To correct this, you assign an order to the entire list.
To assign an order to the railcars in a train:
Select Actions Assign Inbound Order. (For outbound trains, this is Assign Outbound Order)
The XPS displays a message asking "Do you really want to change the order of the this train?"
Click OK.
N4 assigns an order based on the top-to-bottom order of the railcars in the list.
If you make mistakes in the order that are not easily corrected using the above procedure, you can add all of the railcars to an unused (empty) train, then select and add railcars to the train in the correct order.