The lease on Bryn Eglwys expired in 1942, but was extended on an annual basis. The October 1942 Bradshaw's Guide shows two return passenger trains operating only on Monday, Wednesday and Fridays, taking 45 minutes in each direction. No passenger service was provided on other days. Overnight on 26 December 1946, several weakened support columns in the quarry gave way, resulting in a significant collapse; the quarry was deemed unsafe and closed immediately. Haydn Jones had promised to continue operating the railway as long as he was alive and so, despite the closure of the quarry, the railway continued to run trains on a shoestring budget. In 1947 the British railway system was nationalised and the Talyllyn was one of the few operating railways not included. The reasons for this are unclear, but it is significant that all official mention of the railway had ceased several decades before and it is likely that the line was simply forgotten by officialdom. Between 1947 and 1949 the railway ran a passenger service two days a week. In 1949 Haydn Jones, who owned the Aberllefenni Slate Quarry purchased 10 tons of rail from the recently lifted Corris Railway. On 2 July 1950 Haydn Jones died and closure of the railway seemed inevitable, but the line continued to operate for the remainder of the summer season, ending on 6 October.