This is Ballykelly airfield, probably no longer like this, where the railway line crosses a main airfield. In a magazine article it was said that in the control Centre for the 'planes, there is in the corner, among all the computers and sophisticated equipment, two old-fashioned key token instruments, for accepting (or not) the trains to Londonderry. I am told by the RPSI that this airfield is no longer used for fixed wing aircraft, only helicopters. The runway is still crossed by the railway, however!