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Proceedings.] DISCUSSION OX COMPOUND LOCOXOTIVES. 101both goods and passenger, Xr. Webb's three-cylinder engines were &Jr. Worthinglikely to be employed, and the almost untried three-equal cylinder system gave promise of success. The four-cylinder system, while being complicated, presented adrantages of the highest power and nniform well-balanced action.Correspondence. CORRESPONDENCE ON conwoum LOCOJIOTIVES. [1\Iinutcs ofAir. B0ot.h. of one diameter, and their pistons, covers, and rods interchangeable.Any departure from a cylinder ratio of 1 : 2 would be made by means of a shorter stroke to the inside high-pressure cylinder.With such an arrangement, uniformity in shop work would be attained ; the high-pressure cylinder would be kept warm in the smoke-box ; the disagreeable surging motion at starting would be so mitigated as to be perhaps imperceptible, whilst none of the advantages now apparent in the Webb engine would be sacrificed. Further, with three cylinders of uniform diameter, the engine could be used as a simple engine, with boiler steam in all cylinders, and in this way would be enabled to perform an enormous duty for a short time, or for such time as the boiler would provide steam. The difficulty in starting would be overcome by the use of boiler steam in the low-pressure cylinders, the high pressure being then allowed to exhaust independently. Certain extra valves would be needed, FIG. 4. FIG. 5. PROPOSED DESIGN. WEBB TYPE. Downloaded by [ University of Liverpool] on [17/09/16].

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" An Investigation into the Use of Progressive High Pressures in Non-Compound Locomotive Engines." By DUGALD DRUXMOHD, M. Inst. C.E. THIS investigation was instituted to ascertain what increase of efficiency or economy is derived from raising the boiler-pressure in non-compound locomotives, and whether high initial pistonpressures are prejudicial to the mechanism of this type of engine, working under the severe conditions imposed by modern express traffic. The tests took place on the Caledonian Railway between Carlisle and Edinburgh, and vice versci, one of the heaviest pieces of main line in the United Kingdom. The engines selected for this purpose were Nos. 76, 77, 78, 79, built at the Caledonian Railway Company's Locomotive Works, St. Rollox, Glasgow, and put on to traffic in the latter half of 1889. Nos. 76 and 79 have each a working pressure of 200 lbs., No. 77 a working pressure of 175 lbs., and No. 78 a working pressure of 150 lbs. per square inch. They are of the bogie type, with cylinders 18 inches in diameter by 26 inches stroke, and in every respect-except boiler-pressure-identical. The trains selected for experiment were the 4.30 p.m. ex Carlisle from London, and the 10.15 a.m. ex: Edinburgh to London express. These trains were timed to run a t a down mean speed of 51.35 miles an hour; and at an up mean speed of 50.08 miles an hour between terminal stations ; the 50 miles between Carlisle and the summit of Beattock incline, with a vertical rise of 947 feet, having a time allowance of one hour. Thus the conditions under which the trials took place, were of a nature to bring out the respective merits of the engines working under the different boiler-pressures.

The military and its subcontractors continue to drive the need for advances in microelectronics packaging, as seen by the increased use of high pincount IC, VLSI, and ASIC devices.This article examines design criteria and material issues considered to produce high quality nine layer hybrids for GE Aerospace and their advanced IR sensors. These hybrids were manually routed and checked. Subsequent investigations into recent CAD technology showed substantial savings could have been achieved in design time.The nine layer hybrid shown in Figure 1 has a high component count: 44 active devices and 10 capacitors. The package contains 120 I/Os and a maximum substrate dimension of 1.2 x 2.45 inches. This resulted in an area ratio of silicon-to-substrate surface of 35 percent. Real estate remaining was primarily used to terminate greater than 1850 wire bonds.