On 10 June 1869, a northbound goods train left at about 11:45 am bound for . It comprised the
0-6-0 tender locomotive
Antelope (built by
Slaughter, Gruning & Co. in 1857), hauling about forty wagons including a brake van; proving to be too great a load for the locomotive, most of the wagons were detached at . The train left Bedwas at about 12:35 pm with
Antelope now hauling five loaded iron ore wagons, three empty wagons and the brake van. Although a goods train, it was carrying some passengers: together with the driver on the locomotive or tender were J. T. Simpson, the
B&MR locomotive superintendent; John Kendall, the
Rhymney Railway locomotive superintendent; the B&MR inspector of traffic; and a B&MR fitter; whilst in the brake van was a carpenter together with the guard and fireman of the train. The train passed Maesycwmmer at 1:05 pm, and shortly after, whilst passing under the Hengoed Viaduct, it became derailed on a very tight reverse curve. The derailed locomotive ran on for about then struck a girder supporting an underbridge, causing the girder, locomotive, tender and three ore wagons to fall into the road beneath. Of the five men on the locomotive and tender, Kendall and the driver were both killed, the others seriously injured – Simpson later died of his injuries. The locomotive was also damaged, but was later repaired and returned to traffic, eventually being given the number 7 and withdrawn from service in 1881. ==Routes==