I'd go just for a monocolor cycle of trains (Uncommons?) that care about the Rail Line/Rail Die
Whiteline Express
Artifact Creature - Juggernaut
Vigilance
Whenever Whiteline Express attacks, if you haven't rolled the rail die this turn, move your train counter one railroad to the right (
Junction abilities trigger as normal)
2/6
Thought Freighter
Artifact Creature - Juggernaut
Hexproof
Whenever your train counter is removed from the rail line, draw two cards, then discard two cards from your hand unless you discard a land card.
4/4
Possessed Locomotive
Artifact Creature - Juggernaut
Pay 1 life: add
to your mana pool. This mana may only be spent to roll the rail die
Whenever a creature dies, add
to your mana pool at the beginning of your next main phase. This mana may only be spent to roll the rail die
4/4
Lightning-Rail Engine
Artifact Creature - Juggernaut
Haste
Whenever Lightning-Rail Engine attacks, roll the rail die. For that die roll, results of a blank face count as
(
Rolling the rail die this way costs no mana)
5/3
Wildliner
Artifact Creature - Juggernaut
Trample
Whenever your train counter would be removed from the rail line, you may instead move it to any railroad in the rail line.
5/5