A bump train is a connected sequence of rideable wind-swell bumps that lets a foiler link glides downwind, transferring speed from one energy pocket to the next. In parawinging it is what you ride after stashing the wing: pure swell energy, with foil pumps only to bridge the gaps between bumps. Reading the train (where the next bump is forming and which diagonal line connects to it) is the core downwind skill.
The bump train is what powers stashed-wing riding. Stash the parawing and the wind stops driving you; from that point the organized lines of wind swell do all the work. A good train reads like a downhill. Pockets of pressure and release move roughly with the wind, spaced tight enough that a foil carries speed from one into the next.
The reading skills come straight from downwind SUP and prone foiling. Ride the pressure, not the wind direction. Find the downhill line across the water, take diagonals into the bump ahead, and get off a fading bump before it dies instead of milking it to zero. Pump in short, timed bursts to bridge the gaps; constant pumping cooks your legs and wrecks the rhythm. Wake Style’s bump-reading guide and the LabRat Foiler downwind course are the most structured resources going, though neither is parawing-specific yet.
The wing gets you to the train and gets you home. In marginal wind a bump can even put you on foil: MACkite’s S-Start points you 10–15° off dead downwind and pops you up on a swell’s backside. Once connected, riders stay stowed for long stretches. BRM riders report flying under a minute, stashing, then riding a single 45-minute downwind send on swell alone. Drop off foil mid-train and can’t pump back on? That’s your cue to deploy.
Full technique lives in downwind glide and pumping and connecting bumps. The reference run for stacked trains is Maliko. All terms: glossary.