CATERHAM JUNCTION

8th FEBRUARY 1858 

The engine was built by the Sharp Brothers and Co of Manchester, ‘Sharp Bros Singles’ Engine No. 37, and was delivered to the Railway Company in November 1849. In January 1853 there was a new set of tubes put in. The total mileage the engine since it has been in  the possession of the company has been 200,000 miles. Its working pressure when new was from 120 to 130 Ibs. on the square inch; but the working pressure had been reduced to 90 Ibs on the square inch a practice not unusual as engines become aged. The boiler has two safety valves, one of which is locked up and the other has a ferrule under the end of the lever to prevent the pressure being increased. The effect of the explosion on the engine itself was inconsiderable, though it unfortunately resulted in the death of the fireman but left the driver untouched, although quite naked except for his working boots and socks; being confined to bulging inward of the copper fire box  just below the fire box door, which had the effect of drawing the copper from the ends of the stays which were screwed into it. The copper below the fire box door is subject to more than usual wear from the friction of the coke in filling the fire box, and the copper at this part of the fire box was found to be reduced from 7-8ths of an inch in thickness to 1-4th of an inch.

The engine had been run 200 miles the previous day, and the boiler had exhibited no signs of weakness. At 6 a.m. on Monday 8th February, 1858, of the explosion occurred it was employed to take the parliamentary down train to Brighton; the train was assisted up the New Cross incline by a pilot engine, a ‘R. B. Longridge & Co. Goods loco.'  No. 101; when it reached the Caterham Junction, which it did to time, the steam was blowing off freely. After standing there about one minute, the explosion occurred. There can be no doubt that the explosion occurred with steam at the ordinary working pressure. And as this is probably the last report on this description of accident that I shall have the honour of making to their Lordships, I desire to take the opportunity of stating that all my experience goes to confirm the view I have for many years taken, that the majority of these explosion occurs the ordinary working pressure of the steam, and can be traced to the boiler being worn out, or to some marked defect in its construction, and not to steam of extreme tension generated by the wilfulness of the driver loading the safety valves, and which is a favourite theory of locomotive superintendents to relieve themselves from blame; in cases where steam of extreme tension has been generated, it will be found almost invariably to have arisen from the wearing of some part of the boiler.

On the occasion of a very disastrous explosion some years ago at Longsight, near Manchester, an eminent engine builder of the city assumed that the steam had arisen to the enormous pressure of 300 or 400Ibs on the square inch, because that the copper of the firebox had been drawn from the stays in a similar manner as in the case now under consideration, and he had found by experiment that it required a force of that amount to draw copper of a certain thickness from a bolt screwed into it. 

To suppose in the present instance that there was anything approaching to such a pressure would be absurd; the explosion arose from the resistance being reduced by the wear and tear to the working pressure of the steam employed.

The locomotive foreman who had charge of the engine, and who had recently examined it, was of the opinion that the engine was perfectly safe with the copper reduced to a quarter of an inch in thickness, and stated, that he had known engines work perfectly safe when the copper had been worn down to one eighth of an inch in thickness; and I know that many locomotive engineers hold the same opinion; but this explosion, and two others that have recently occurred, owing to the wearing of the copper, show that it is not safe to trust to the tenacity of the material, when from long use it has been worn down to half its original thickness. The locomotive superintendent proposes for the future screwing the stays into nuts on the inside of the firebox, instead of into the copper, which would much increase the area of resistance; the idea is a good one, though not new, as I have seen fireboxes constructed in this manner; but though a good precautionary measure, it should not induce companies to allow fire boxes so much reduced in thickness to be used.