Well, I had a sit down and a think about how a loco-loco could be used in SAEaE. This jumbled stream of consciousness is what I've got so far:
1. A one-off event: ie once per game only and only in games where there is a track.
2. Attacking Player declares his intention.
3. Place loco loco on track on his baseline
4. Throw 1D6 each time attackers have initiative: move that number of squares
5. Loco-Loco not subject to activation but does count against number of units attacker can move each turn. EG if attacker rolls 2 on 1D6 then 1 unit plus the train can move.
6. Train continues until it strikes target area or is de-railed.
7. Defender can place mines on track: throw 1D6: 1,2 = 2 mines, 3,4 = 1 mine, 5,6 = 0 mines
8. Place mines on track: marker of some kind
9. If train passes over mine throw 1D6: 1,2,3 mine triggered; 4,5,6 mine failed.
10. If mine triggered throw 1D6 to see if train derails or is going fast enough to jump the gap: 1,2,3 Jumps; 4,5,6 Derailed.
11. If derailed throw 1D6 to see if explosives detonate. If explodes then damage occurs as in 12.
12. On contact with target train automatically explodes and all units within 1 square/3 hits, 2 squares/2 hits, 3 squares/1 hit. Hits apply to attacking and defending forces. No saves.
I will do some play-testing on this lot and report back.