Pigeons,
Hardly a leap of imagination. The ramp is around 4 feet in width, the Tugs wheel track is over eight. The tug drives in, and straddles the ramp, the aircraft nose wheel rides over it, in the process lowering the aircrafts tail, avoiding a coming together with the overhead hangar structure. An admirable solution to putting aircraft in hangars, not designed to accommodate their dimensions. I well remember the jiggling required to extract gliders from hangars whose orifices were less than the gliders wingspan. And of course, the F shed resolution at Abingdon with the Belfast, where the aircraft nose wheel was put on a raised "skate" to lower the tail and allow its unimpeded acces to the hangar. Hope that helps.
Smudge
