How do you know the train number?

[smokemyshorts]

I see lots of pictures on Facebook, Instagram, web sites, etc. where the photographer will say something like "NS 2542...leads C702 southbound...." How do you know the train number? How do you know that specific train is C702, for example? Are you using train schedules? Are you listening to radio traffic? I still haven't figured that out. Please direct me to more information about this topic. Thanks.

 

[EMDGP30]

Listening to a scanner is how most people can find out the train #. Also, if you know someone that works for the railroad they can print out a schedule with train #, engines and train length.

Back in the 80s when I used to railfan a lot, I had a friend that was a MTO at the local UP yard and he would print me out a line-up for Tower 55 in Ft. Worth when I drive over and spend the day.