His flights with Sam had never been especially smooth or planned either, so Bucky didn't find the experience too different, though it was definitely not his preferred method of getting around.

And thankfully Bucky had the reaction time to take the brunt of the weight for them, mirroring that grip round Tony's waist with his flesh and blood arm and catching the edge with the vibranium one. Judging by the gritted teeth and pained grunt it didn't feel too great to him either, but it held a hell of a lot better than Tony's joint would've.

Hoisting them up, Bucky stalled only long enough to make sure Stark could pull himself up the rest of the way before racing after the train to try and catch it before it disappeared from sight.

It was a long chase before he caught up, into the tunnel, just shy of hopping onto the outside when he slammed face first into an unseen forcefield. It fully laid him out for a moment, and he was grateful not for the first time that Sam wasn't there with Redwing to see him in moments like this.

His face was a mess when he walked back out, and he flashed Stark an uncomfortable, stiff smile. "...Yeah, there's barrier in there," he informed, as though that wasn't obvious.