continuous brakes on it would be released, and the only brakes holding it against the gradient would be the hand-operated brakes in the rear brake van. For a goods (freight) train in a similar situation, the wheels would have been 'scotched' against roll-back, and guard's vans on goods trains carried 'sprags' with which to do this. Those on passenger trains with continuous brakes were not required to carry sprags, and the excursion train did not. The guard in the rear van having applied his handbrake then (on the instructions of the chief clerk) dismounted and scotched the wheels of his van with pieces of ballast. He then also scotched the near rearmost vehicle on its righthand wheels and intended to similarly scotch its lefthand wheels before going back down the track with flags and detonators to protect the train from the scheduled service which was to set off from Armagh 20 minutes after the excursion. The train was screw-coupled; each carriage was first coupled by a loose chain and hook coupling to the next; the slack on this was then taken up by a turnbuckle screw arrangement, until the buffers of the two carriages were touching. To uncouple, there needed to be some slack in the coupling; as the train had stopped all the couplings were under tension. Once the vacuum brake connection to the rear portion was broken, any attempt to introduce slack into the coupling between the two portions would be defeated by the rear portion settling back to rest its weight upon the rear van brakes. To assist uncoupling the front van guard therefore scotched one of the wheels of the sixth vehicle, that is, the front vehicle of the rear portion being detached. Loosening the turnbuckle thus transferred the weight of the rear portion to the scotch on the sixth vehicle, rather than to the rear van brakes. The couplings to the rear of the sixth vehicle remained under tension, and the slack introduced remained in the coupling between the fifth and sixth vehicles, which could be unhooked. The rear carriages run away The uncoupling accomplished by the front van guard, the driver attempted to start the front portion away. It rolled back slightly, jolting the rear portion; which caused the wheels of the front vehicle of the rear portion to ride up over the stones underneath them. The rear portion had been standing with its