IN a paper on “High-Pressure Locomotives”, read before a crowded meeting of the Institution of Mechanical Engineers on Jan. 23, Mr. H. N. Gresley, the chief mechanical engineer of the London and North-Eastern Railway, gave an account of the various high-pressure locomotives constructed in the United States, Germany, Switzerland, and England since 1924. Prefacing his remarks by observing that at no time during the history of the steam locomotive have such radical changes been introduced as during the past ten years, he said that in Great Britain alone there are 23,000 locomotives, on which a sum of £45,000,000 per annum is expended on maintenance, renewal, and running. About 25 per cent of this is the cost of fuel and another 25 per cent the cost of maintenance and renewal. It will be noted that the expense in maintaining locomotives is equal to the cost of the great quantity of coal they consume. From this it is clear that there is a wide field for economy if both the cost of fuel and maintenance can be reduced.