Thanks for the info storm.
Please ask him to check if all long cars are correctly attached to the trains not by highlighting them but by clicking in the locomotive and then see if all the long cars have a white background in the Freight cars tab.
If all is correct, then delete both of you as superneighbors again.
You both run memcache and close your computers.
Restart both computers and add you both back as superneighbors and add permissions again. You both have to reload the game and then you can try to dispach the trains again.
If nothing helps, then contact Support. To contact Support click on the link below, fill out the form and submit it. Be patient as it can take anywhere from a few hours to a few days for them to respond to you depending on how many tickets they have ahead of yours.
http://apps.facebook.com/farmtown/settings2/support/
You will receive an automatic response email when you submit your ticket. That email will have your ticket number and a link for you to check the status of your ticket, so please do not delete that email. If you do not see the email then check your spam folder as sometimes those emails get classified as spam.
If you are having a problem getting responses from Support please read the information in the following link:
http://www.slashkey.com/forum/showthread.php?t=644366