Many tourist railroads run theme trains. Dinner trains, Halloween Spook Trains, Ice Cream Trains, Polar Express or some variation of “Christmas Train that doesn’t violate PE trademark”

However, I’m interested in the oddities. What’s the strangest one you know of?
Steampunk Trains are a bit unusual, but they seem to be getting popular.
Heber Valley has a Wizard Train, anyone else doing a D&D type theme?
The strangest I can think of is the Pinball Pendolino at Strasburg. Does that still run?

The Durbin & Greenbrier/West Virginia Central ran a "Spam Train" in 2015.

Spam, as in the stuff in a can, not the junk email......

I kid you not.

I'll believe it, there is a Spam MUSEUM in Minnesota:

https://www.spam.com/museum

Spam, spam, spam, spam...

(For the Monty Python fans here)

I haven't seen any Pinball trains advertised for Strasburg after that first year, sadly. Hopefully someone from the RR can chime in with a more detailed answer as to why/why not.

I have seen a very interesting take on the Halloween trains - the Fillmore & Western will be offering a "Zombie" train this year, complete with trackside zombies that participants can shoot at with paintball guns while onboard... http://zombiehuntertrain.com/

The Wilmington & Western in Delaware runs a hay ride train in the fall (diesel-powered, of course).

The pinball car on at the Strasburg was removed from the train in 2016 when I was working there. The demand was minimal and the person who was in charge of maintaining the pinball machines had a hard time keeping them running, with only a few in service at a time.

JR West has a Hello Kitty bullet train. Maybe not what you expected. I understand there is also a Panda themed train among others.

https://www.jrailpass.com/blog/hello-kitty-shinkansen

The Orlando & Northwestern (The Florida Train Experience) has "Rumrunner" booze trains which are pirate themed despite being 1. a train and 2. no where near the ocean.

Then there's the St. Mary's Railroad in Georgia that doesn't so much have weird trains so much as all of them end with the train pulling up along a stage built out in the middle of a field and these weird amateur plays are performed.

The Minnesota Streetcar Museum does:

PJ Party

Put on your jammies and grab your best bear. Then head for the Linden Hills Station at Lake Harriet for the PJ Party. We’ll start with milk and cookies on the platform, then board the streetcar for a trip down the line. We’ll stop for a bedtime story from a noted children’s author before we return to the station.

The Heber Valley Railroad has a 'Princess & Pirates' train that usually sells out. It's a weird one, but it's a great example of very creative marketing.

Pot is legal in this state so a few people have suggested that a local museum run pot (as opposed to wine) trains. For several this has not happened.

The Illinois Railway Museum runs the "Bunny Trolley Hop" at Easter time, basically a Santa train type operation featuring the Easter Bunny instead of Mr. Claus. The kids get to meet the Easter Bunny on the streetcar, which takes them out to an Easter egg hunt; outside if the weather is nice, in one of the carbarns if it is not. According to the Rail & Wire, the museum newsletter, it's been pretty successful.

Fillmore & Western in SoCal runs zombie hunter trains. They are open cars with paintball guns to shoot at the zombies. They always sell out!

The Sacramento River Train ran a similar train a few years ago. Albeit, not as successful.