Roll up identities, secret identities and goals for about 6 passengers, then put them in a list and give each a relationship with the passenger below them. Finally, roll to see which one is killed 1D4 days into the voyage, and again to see who did it. You may also, if you wish, roll for a mystery gimmick.
1. Fat Russian royalty, always laughing
2. Twins from Austria, beautiful, talk between themselves in made-up language
3. Nikola Tesla equivalent, old and broke
4. Old french artist, makes depressing speeches, no-one listens
5. African Indiana Jones equivalent
6. Italian preacher, nervous and clumsy, takes instant dislike to one of the PC's
7. Jazz singer with 12-person Big Band from London, constantly drunk and celebrating
8. German, tall and reserved, obsessively collects [insert something the PC's own]
9. The Mum of one of the PC's. Here on holiday.
10. Scottish author, stays in cabin writing book for entire journey, yells at intruders with unintelligible accent
11. Young english kid travelling alone, bitter beyond years
12. Excitable Australian inventor, working on fantastic cure that could be misused as a horrible weapon
13. Swiss couple with identical sets of scars all across bodies, consider themselves the same person
14. Frail, sick-looking Russian with massive amounts of kids that swarm everywhere
15. Haruspex, has small menagerie of animals, cheerfully foretells dire omens from their organs
16. Masked plague doctor from Venice, speaks with mechanical rasp,
17. Turkish Magician, Hypnotist and master of illusion, will obsessively try to divine the trick behind any real magic they see
18. Shakespearean actor, alternates between overblown speeches and tired self-consciousness
19. Hard-nosed railway brass, making sure the journey goes smoothly
20. Prize german boxer, with daughter. Super aggressive except in sight of kid.
1. Utterly disgusting slithering wet black thing, mind-controlling passengers and PC's to like/love it
2. Anarchist rebel, concealing bombs
3. Actually mute idiot controlled by ventriloquist shadow
4. Exactly what they seem to be
5. Keeps fridge full of virgins, will begin to shrivel into skeleton if they don't bathe in their blood for 3 days
6. Bank robber, getting away after successful haul
7. Secret agent of Coldsnap, communist-nazi spy organization
8. Keeps heart in cage in room. If heart is released, will grow legs, escape, and sabotage train.
9. Secretly a large group of clones, each takes turns to act as them
10. Time-traveler Future PC in heavy disguise
11. Spy for [powerful faction], left hand detaches with a bunch of rope to act as grappling hook
12. Insect, burns if exposed to true darkness
13. The president of the United States
14. Cuts a piece of themselves off each night, making tiny doll with them
15. Heir to throne in hell
16. Ice robot from another dimension
17. Powerless volcano god from a forgotten old religion, desperate for worshippers
18. All servants/followers/acquaintances are zombies. Hates them, but owes them debt; they stick with them to make sure it's paid.
19. Minor character previously encountered, obsessively in love with PC's, on train to stalk them.
20. Cultist servant of [Nearest Cthulhoid monster]
1. In servitude to
2. Having secret affair with
3. Conspiring with
4. Has power over
5. Killed personal friend of
6. Secretly related
7. Married to
8. Signed dark pact with
9. In reverential awe of
10. Sworn to destroy
11. Secretly buying weapons from
12. Knows secret identity of
13. Stealing from
14. Prostitute of
15. Sibling of
15. Sibling of
16. Student of
17. Challenges to duel over perceived slight
18. Taking care of
19. Good friends with
20. In debt to
1. Sell a weapon in Venice
2. Meet leaders in Moscow
3. Rob train
4. Destroy train before it reaches [next stop]
5. Claim inheritance in Paris
6. Escape police from [previous stop]
7. Hunt down their enemies in Venice
8. Stop Berlin from going to war
9. Go to China to die
10. Seek Wisdom in Himalayas
1. An invisible train car is secretly attached to the end of the train. Horrible things are inside.
2. 2D4 Highway robbers attack train 1D10+2 days into journey
3. Train is sentient, evil, coal must be constantly sacrificed to it to appease it
4. Train driver is chained demon, will offer anything for freedom
5. Everyone committed the murder
6. The murder victim is still alive
7. The Jade Cage, absurdly valuable ancient artifact with space-warping powers, is aboard.
8. A Nuke is on board
9. An axle breaks 1D10+2 days into the journey. Looks like sabotage.
10. Train misses stop and keeps going at high speed - drivers cabin is locked tight
Originally posted on my other blog ages ago. Sorry for how many different rolls you have to do.