underground railroad Definition

underground railway, metro, subway, tubman, slave, tube, tubes, harriet tubman, tunnel, canada, ore, gate, manhole, shoe, shoeing, torpedo, torpedoing, tram, underpass, culvert, hard, doodlebug, baker, booby trap, burrow, core, coring, dig, gating, grounded, mainline, putter, ramp, sewer, silo, sled, spad, spout, spouted, spouting, spy, stile, surface, tunneling, vault, colliery, conduit system, gas pump, gasoline pump, island dispenser, alignment, amtrak, ballast, bed, bef, block, bonnet, brd, caboose, car, coach, conductor, corner, cowcatcher, creep, creeps, crew, crewed, crossover, cutting, depot, derailing, derailment, detrain, dolly, fast track, filk, fill, fills, flourish, flourishing, freight, frog, fusee, gantlet, gauge, grade, grip, gripping, guard, highball, hobo, indicator, locomotive, monorail, passenger, platform, rail, railroad tunnel, rails,