If Sherlock Holmes were a character in real life instead of a novelist's puppet, he would find just now a more profitable field for his talents in the investigation of accidents than in that of crimes. The mind of the British public has been made seriously uneasy, by a succession of railway disasters for which no adequate explanation has hitherto been forthcoming. The last of the series was the derailment at Shrewsbury on October 15 of a London & North-Western express from Crewe to South Wales, with the result of several deaths and a large number of injuries. What makes this accident especially alarming is its close likeness to the two most serious disasters of 1906the derailment of an American boat express at Salisbury on July 1 and that of a Great Northern express at Grantham on September 20. The points of similarity are as follows: In each case the accident occurred at night to a fast express train when traveling, at a higher speed than normally permitted, around a curve close to an important station where switches and signals are abundant. In each case, also, the engine driver was a steady and experienced man, and both he and his fireman were instantly killed, so that it has been impossible to gain any first-hand testimony as to why the signals and the speed regulations were ignored. At Salisbury and Shrewsbury the derailment occurred on the curve itself, but at Grantham on a straight piece of line immediately following it. The Shrewsbury driver was running at sixty miles an hour over a portion of the track where ten miles was the official rule and twenty the highest speed consistent with safety. This apparent neglect of definite orders has naturally directed much attention to the "human factor." May it not have happened, people are asking, that the driver was seized with some sudden illness which rendered him incapable? This theory has been generally pooh-poohed by railway men themselves. At the Board of Trade injuiry at Shrewsbury both a locomotive foreman and a locomotive superintendent declared emphatically that they had never known an instance of a driver collapsing while on the footplate. It so happened, however, that only a few days after this evidence was given, a Midland driver actually died on his engine, though apparently in good health at the beginning of his journey, and two or three other instances of paralysis, etc., under similar conditions have since been published. After the Shrewsbury accident Mr. Lloyd George, the president of the Board of Trade, took the unusual course of ordering an autopsy to be performed on the body of the driver, and the surgeon's report showed that in this case, at any rate, there was no physical failure. Another, suggestion is that the engine driver, while far short of an entire collapse, may have had his wits temporarily dulled by an insidious drowsiness. The editor of the automobile column in the London Times lays great stress on this possibility. At least one serious automobile accident, he says, has been due to the chauffeur's falling asleep. He has himself over and over again, when rushing rapidly through the air, felt not so much a desire to sleep as a physical inability to remain awake. It came over him with an irresistible force, which he could not stop by changes of position, or violent shakings of the head, or even pain deliberately self-inflicted. Other motorists, he declares, have confessed to him a similar experience. Quite independently, a railway man of many years' standing offers a similar explanation in the Pall Mall Gazette. When working as a fireman on a fast train, he has many a time looked up and seen the driver standing as it were in a dream, quite oblivious of any signals. On hearing the fireman's voice of warning, the driver at once came to himself and everything was all right. In the judgment of this correspondent, it is significant that in these recent disasters the driver, an elderly man, had as his companion on the engine a man who was not his ordinary mate. Now a strange, and especially a young, fireman is not in touch with his driver. He is likely to be attending more closely to his own particular duties, and if his driver goes "wool gathering," he has no opportunity of noticing it. At the same time, the staying power of the average driver is decreased by reason of his having to take longer journeys than formerly. One may add that the risk of such a lapse is all the greater when the journey is at night, and when, as at Shrewsbury, a heavy rainstorm causes the signals to stand out less clearly than usual. It must also be recognized, in connection with the "human factor," that a driver has often a strong temptationtoo strong a temptation, some sayto run at excessive speed in order to make up for lost time. The Shrewsbury train, however, was so nearly on time that this explanation scarcely fits the present instance. We now turn to the theories which explain these disasters as due to some mechanical defect. It was the unanimous opinion of the jury at the coroner's inquest upon the victims of the Shrewsbury accident that the brake power of the train was insufficient. There can be no doubt, according to the evidence, that the brake was actually applied. The guard testified that at Crewe Bank, where the danger signal was passed, he found the train traveling too fast/ He went to the hand brake, and found the vacuum brake already full on, but with little diminution of speed. A Board of Trade inspector who examined the wrecked engine found that the brake had been fully applied, with no appearance that it had been in any way inoperative. Railway officials, in commenting upon- the catastrophe, will not admit for a moment that the brakes can have been out of order, and declare that their experience gives no confirmation to the possibility of any such cause. A very different position, however, has been taken by several drivers who have communicated their views to the press. They affirm that they have known many instances in which serious disasters frdm brake failure were averted by a very narrow margin. "Some years ago," says one of them, as reported in the Manchester Guardian, "I slightly overran the place that I should have stopped at, owing to this cause. When the official came to investigate it, I told him the brake did not go on when applied. He said, 'You must not say that; if you do, you will be discharged. ' " It is stated by other drivers that instances of the delay or failure of brakes to act are never reported because "the bosses will never admit the brakes are wrongit's always the driver." And a passenger in a signed letter to the London Tribune relates the following experience: "About two years ago, while I was waiting for a train at Harrogate station, an express train came in on its way to King's Cross. When the time came for the train to resume its journey H did not move, and in answer to the superintendent the driver said the automatic vacuum brake would not act. After twenty minutes' delay the train started on its journey. Is not the conclusion inevitable that these brakes get out of order more frequently than we read of?" It may perhaps be as well to mention here, for what it is worth, a theory that the heavy downpour of rain kept the metals covered with a film of water upon which the locked wheels glided so that the train ran away. It has also been suggested that, while there was no fault with the brakes, the driver found it impossible to shut off steam; that the valve spindle, under the high working pressure, had expanded or even broken. The brakes alone could not stop a train traveling at sixty miles an hour under steam. Realizing his helplessness, the driver then resorted to the only method left of checking his train, namely, reversing his gear, which, according to the evidence, was done just before the crash. In the course of the correspondence on this subject, publicity has been given by the Yorkshire Observer to a theory of Mr. T. H. Brigg, formerly of Bradford, England, but now of New York. His opinion, in brief, is that accidents of this kind are largely due to the modern type of railway car with its double bogie, as compared with the old-fashioned ear, with four or six wheels and a rigid wheel base. Although the bogies give flexibility to a train in rounding a curve, the long bodies of the cars remain rigid, and the buffers on the inside of the curve are all Rightly compressed, while those on the outside may possibly not even touch one another. When the driver opens the vacuum brake, the wheels of the engine and tender are power- fully retarded, but the rear cars crowd-forward for a time. If the train is on a curve, the inner buffers only are compressed, and the sixty-foot frame of the car becomes an enormously long and powerful lever, operating upon the inner buffer of the car in front to force that car off the track toward the outside of the curve, the fulcrum of the lever being the pivot on which the front bogie turns. Some confirmation is given to this theory in the Shrewsbury case if the brake, as previously suggested, although put on a mile or two back, did not begin to act until the train was actually on the curve. Mr. Brigg's theory, it should be added, is quoted as applicable to the accident which occurred not long ago on an elevated track in the Bronx. Another mechanical explanation has been offered by Mr. James Keith, a London engineer. He believes that no derailment would have occurred in any of these cases if the wheels had had "the proper depth of guide flanges so called, instead of the little half-beads which usually keep the wheels on the track at moderate speeds." He maintains that the only thing which keeps fast trains from derailment on curves under these conditions is the great weight of modern locomotives and cars bearing on these wheels. This weight, "though a safety at high speed when every point is carefully attended to, becomes a real danger when the train has the slightest inducement to leave the track, as, for instance, on the too sudden putting on or taking off the brakes, or the failure of the brakes to act, or the sudden reversing of the engine, or with one of or all these together and the metals, say, 'greasy,' and because of the extreme oscillation of the present-day huge locomotives and coaches." No change, he points out, has been made in the guard margin of the wheels during the last fifty or sixty years, though the speeds of all trains are on an average at least twice what they were when the said wheels were originally designed. With so many theories to account for these disasters, it is not surprising that numerous suggestions have been offered for their prevention in future. Among the principal reforms recommended are the more frequent medical inspection of engine drivers; the limitation of the journey to shorter runs; the provision of an extra man on the locomotive or of some better means of communication between the engine and the guard's van; the repetition of signals in the cab of the locomotive by a mechanical contrivance; the use of detonators as warnings at dangerous places at night; and the straightening of curves. The last-mentioned suggestion has been strongly supported by Mr. Andrew Carnegie, writing as an ex-railway superintendent to the London Times. No regulations, he says, can insure safety on such sharp curves, which therefore should not be allowed to exist.