...If the NPC doesn't introduce himeself, you are NOT on a railroad.
If the NPC introduces himself as "Bigsley the Merchant," you MIGHT be on a railroad.
If the NPC introduces himself as "Elminster," you are ARE on a (crappy) railroad...
Take my quasi-omniscient NPC wizard advisor... please.
THE KNOCK-KNOCK JOKE...
I can't take all the credit; I got the idea from pawsplay's post.LOL!
Perfectly describes both extremes...and funny to boot!
Pure Awesome!![]()

(Dungeons & Dragons)
Rulebook featuring "high magic" options, including a host of new spells.