The Brennan Mono-Rail

Timaru Herald, Volume XIC, Issue 13397, 21 September 1907, Page 3 (Supplement)

The Brennan Mono-Rail

' If we may judge by the line taken by the "Scientific American," the way for the single-rail invention of Mr Brennan is by no means clear yet. In its issue of March Btli its editor says that " Of course it is a far cry from the model to the structure of a size and weight of a modem railroad train ; and at the first blush it would seem as though the weight of gyioscopes of the size necessary to impart the required stability would ba so great as to rob the invention of all practical utility." Further, he says, that as the inventor calculates the weight at only five peir cent.' of the total load, or say about three tone for a sixtyton Pullman car, "it is certain that the fly wheel rivust' be run at an enormous speed, at a speed so high that it becomes a matter of speculation as to what kind of. metal can be found' to withstand the enormous centrifugal stresses that wouldbe involved. Furthermore,; it must be remembered! that failure of the rotating mechanism would mean -thelres of all stability to the'train, and that just here, in the" unlikely event' that the invention should) prove to be mechanically practicable, would be a constant source of peril, which might well detract from its popularity with the travelling public." A fortnight later, after the drawings and descriptions of the trials-of the model' have been mad? public in Britain and reached America, the editor returns to the charge with an even worse opinion, for he says plainly that " Were it not for the fact that its inventor bears a distinguished name, and that the exploitation of the device occupied two hours of the time of the last moeting of the Royal Society in London, the Brennan gyroscopic locomotive would deserve no further notice, than is usually given to any inteiresting scientific toy. At tli? present writing indeed ib cannot be regarded as having demonstrated its practical value, at least as applied to heavy train's of the kind that are now running on the railway systems of the world. The model locomotive exhibited before the Society was only six feet long, and, judging from the illustrations, must have been of rather light construction. We should be prepared to find that the weight and power of the gyroscopes would quickly increase

to a point where they would' be prohibitive."

The editor admits at the same time that, so far at, the model itself is concerned, the result of tlia trials was everything that could be desired-; and in the description he had himself given of the apparatus occuis the best we have yet seen of the. gyroscopic part of -ths invention. "In the model," says the editor, "as shown, there is a small closed compartment at the forward end of" the car, and in the after part of this, mounted on tbe floor of the car. is the double gyroscope which serves to maintain the ear in equilibrium. The gyroscopes are mounted in an air-tight case in which a partial vacuum is partially maintained. They rotate in opposite directions in a vertical plane at the high speed of 7500 revolutions p;r minute. Piovisidii is made for assisting the gyroscopes in returning quickly to the horizontal plane. The object of running the gyroscopes in vacuo, is,- of course, to get rid of ths skin friction of the air, and Mr Brennan claims that ha has been so far successful that ths model will remain standing upright on its sing'.e' rail for a considerable time after the current ha-3 be:-n cut off." As the editor shows that he has realised the claims of the inventor as to the practicability of running the full nized gyroscope at the high speeds necessary to compensate for the' low weight, his failure to refer again to his first adverse opinion, as above quoted must be regarded as a sign that he is still unconvinced' by the fuller , information afforded.

In engineering circles here the opinion is fiesly expressed that even if th? apparatus gives ths results promised by the model, the; invention will not be of great use for heavy traffic requiringvdong trains of wagons, such for, example as mineral traffic) as th.' expensei of ■ the gyroscope on each car —for that nivet necessarily ba involved' —would be prohibitive. 'Moreover, it is thought that for shunting purposes the invention would be unworkable.—(" Pi ogfess.")