Originally Posted by Thadeum
I think the opposite, that it is not really plausible. A long distance separates the town from walkers where you left them behind, and there is very few chance this guy saw the railroad from above. Also, there are a lot of walkers already infesting the city. It does not really change their situation.
Well, aside from the fact that I'm fine with agreeing to disagree, I still disagree. In TWD universe, a herd is formulated by straggling walkers so walkers in the city would have tagged themselves along with the horde coming from the railroad tracks. Which would have made an even larger herd of them. Large enough to bridge the distance between what was already in the town and what was coming to the town. PLUS we now have all the walkers from Crawford who are probably loose now that the group has left. Ample opportunity for them to merge and I'm guessing Vernon saw it but didn't want to alert the rest of them.
I DO agree about the train being a good way to transport the ill but I still don't think that's what they did...or why.