For train-lovers, the restoration of Amtrak service between Boston and Portland a few years ago was a small but sweet victory. In this era when rail travel has ‘‘the disappearing railroad blues,’’ as songwriter Steve Goodman put it, it’s hard to imagine that a little over a century ago you could hop a train in Boston and, a few changes later, arrive on the summit of Mount Washington. Four-dollar-a-gallon gasoline may yet revive train travel, but for the time being, railroading is an exercise in nostalgia. It may take all 10 of these excursion trains to equal the hoboes’ Wabash Cannonball, but among them they ape that mythic train that ‘‘glides along the woodland, o’er the hills, and by the shore.’’ On some of these journeys you might meet the rail buffs who saved the cars from the scrap heap, rebuilt the rust-seized engines, and even laid some of the track. All aboard!