On 26 Jan 1921 an express and stopping train collided at Abermule, Newtown.

Seventeen people were killed including [his brother-in-law] Herbert Lionel Henry Vane-Tempest (age 58), a director of the railway.

"The driver of the down train was oiling his engine at the moment when the tablet holder was handed to his fireman by relief-stationmaster Lewis. It is clear that neither he nor the fireman could have examined the tablet before the train started from Abermule. It is also clear that neither Lewis, Jones, nor Thompson could have looked at the tablet instrument for the Abermule-Newtown section, otherwise they would have seen the indicator showed that a tablet had been withdrawn for an up train. After the down train had started (about 12.3 p.m.), presumably when he returned to the booking office to send the "entering section" bell signal for the down train to Newtown, and the "out of section" bell signal to Montgomery, the terrible mistake that had been made was discovered by Thompson, and Lewis realised that he had given the Montgomery - Abermule tablet to the down train. Lewis telephoned to Newtown to ask if the express had left, and was informed by Brock that it had left at 11.59 when he had sent the "entering section" bell signal. A vain attempt was made to attract the attention of the enginemen of the down train, by lowering and raising the up distant signal, but probably by the time this was attempted, the train had passed the signal post, about 660 yards from the loop points...

When [fireman] Owen recovered, he found himself on the ground just behind the second vehicle (No. 310) of his train, which was lying across the railway on top of the first. He saw driver Jones on the opposite side just behind and underneath the third vehicle, which was leaning over towards the slope of the cutting. He got across the framing, and found Jones more seriously injured than himself, and anxiously enquiring whether they had the right tablet. He assured him on the point, but a little later, as his driver was still anxious, he went to look for the tablet and crept under the frame of No. 7730 for the purpose. After a little search he found both tablet holders lying on the ground to the left (north) of the track alongside the wreckage of the two engines. He picked them up and found that one of the tablets for the Montgomery-Abermule section had evidently been carried by the down train. He then returned and showed them to his driver to relieve his anxiety. He subsequently handed the tablet holders to traffic controller Morgan, who travelled in the down train. Morgan eventually passed them for custody to chief traffic inspector George. The latter, immediately after the accident, returned on foot to Abermule, where he arrived at 12.18 p.m. and arranged by telephone for the dispatch of medical and nursing assistance from Newtown."

Herbert Lionel Henry Vane-Tempest: On 06 Jul 1862 he was born to George Henry Vane-Tempest 5th Marquess Londonderry and Mary Cornelia Edwards Marchioness Londonderry. The Times. 02 Feb 1905. The funeral of Lord Henry Vane-Tempest took place yesterday in the family vault in St. Peter's, Montgomeryshire. The Bishop of Bangor, assisted by the Rev J. Williams, rector of the parish, and the Rev. S. J. Evans, officiated. The principal mourmers were the Marquis and Marchioness of Londonderry (brother and sister-in-law), Lord Herbert Vane-Tempest (brother), and Mr. Beaumont, M.P., and Lady Aline Beaumont (brother-in-law and sister). Continues. 09 Feb 1915. Times Newspaper Obituaries. The news of the death of the Marquess of Londonderry, which occurred at Wynyard, Stockton-on-Tees, yesterday morning, will be received with profound regret far beyond the circle of his personal friends or of the members of the Unionist Party. Lord Londonderry had not been entirely well for some little time past. For a fortnight, it seems, he had been suffering from sciatica. Last week he caught a chill, from which pneumonia developed. On Sunday his condition was seen to be critical. During the night he collapsed, and the end came at 9.30 yesterday morning. Lady Londonderry, who had been in constant attendance on him during his illness, was present at the last, as also were Lady Ilchester and Lord Herbert Vane-Tempest.