Interesting. That was a nice falafel sandwich! The 4 berth compartment reminds me of a similar one on the Trans-Siberian, but the Iranian one is much more modern. And the Iranian toilet was much cleaner, but it was at the beginning of the trip... 2nd Class toilets on the Trans-Sib are horrific. Or were on my two trips. I have a feeling getting people to actually do the cleaning en route is less of a problem in Iran, but that is just a guess.
I love train travel but I have to admit that I probably wouldn't be using a camera so obviously in Iran. Probably my American anti-Iranian programming kicking in. I took Khameni seriously when he said, "All Americans are savages."
I would love to travel in Iran, the food can be great. Polo, Tahdig or Sabzi Khordan, maybe buy some smoked fish at one of the stops, but make sure you dispose of the fish remnants outside the compartment! LOL!
Excellent trip!