Amtrak, Charley, L, Trojan horse, VC, Vietcong, abstruse, agreement to disagree, alienated, alienation, alternative, antiestablishment, apostasy, at odds with, at rest, at variance with, avant-garde, back-door, back door, back stairs, back way, backstairs, baggage train, beclouded, behind the curtain, behind the scenes, behind the veil, blind, bolt-hole, branch, breakaway, buried, bushfighter, bushwhacker, cable railroad, cable railway, casual, choo-choo, clandestine, close, clouded, cog railroad, cog railway, collaborationist, collaborator, concealed, counter-culture, covered, covert, covert way, covertly, crypto, deep-buried, difference, differing, disaccord, disagreeing, disagreement, disapprobation, disapproval, disparity, dissatisfaction, dissension, dissent, dissentience, dissentient, dissenting, dissidence, dissident, diversity, dropping out, eclipsed, el, electric, electric railway, electric train, elevated, elevated railway, embankment, escalier derobe, escape hatch, escape route, experimental, express, express train, extremists, feeder, feeder line, feline, fellow traveler, fifth column, fifth columnist, flier, fraternizer, freight, freight train, freighter, funicular, furtive, goods train, gravity-operated railway, guerillas, guerrilla, hid, hidden, hidlings, hole-and-corner, horse railway, hugger-mugger, in a cloud, in a corner, in a fog, in a whisper, in darkness, in eclipse, in hidlings, in opposition, in purdah, in secret, in the background, in the dark, in the wings, incommunicado, insurgents, insurrectionists, interurban, irregular, junction, latent, light railroad, lightning express, limited, line, local, main line, maquis, maquisard, metro, milk train, minority opinion, monorail, mysterious, nobody the wiser, nonagreement, nonassent, nonconcurrence, nonconforming, nonconformist, nonconformity, nonconsent, obfuscated, obscure, obscured, occult, opposing, opposition, parliamentary, parliamentary train, partisan, passenger train, private, privy, quiet, rack-and-pinion railroad, rack-and-pinion railway, rack railway, radical, rail, rail line, railroad, railroad train, railway, rattler, recondite, recusance, recusancy, recusant, rejection, repudiation, resistance, resistance fighter, resting in peace, revolutionary, roadbed, roadway, rolling stock, saboteur, secession, secluded, secluse, secret, secret exit, secret passage, secret staircase, secretly, sectarian, sectary, security risk, sequestered, shifty, shuttle, shuttle train, side door, sidetrack, siding, skulking, slinking, slinky, sly, sneaking, sneaky, sotto voce, special, stealthy, streamliner, street railway, streetcar line, sub rosa, subterranean, subterraneous, subversive, subversives, subway, sunken, surreptitious, switchback, terminal, terminus, track, train, tram, tramline, trestle, trolley line, trunk, trunk line, tube, turnout, under-the-counter, under-the-table, under an eclipse, under cover, under house arrest, under the breath, under the rose, under wraps, undercover, underfoot, underground fighter, underground railroad, underground route, underhand, underhanded, unknown, unobtrusive, variance, way train, with bated breath, withdrawal, wrapped in clouds