High-speed rail circa 1907

An interesting look at how people looked at advances in transportation around the turn of the last century. From the 1907/03/09 Scientific American. [Emphasis added]

A HIGH-SPEED BAVARIAN LOCOMOTIVE BY WILLIAM MAYNER

The locomotive illustrated herewith was exhibited at Niirnberg; it was designed expressly for a normal speed of 94 miles an hour. Judging from the previous results obtained with the remarkable locomotives of the same builder, J. A. Maffei, of Munich, it is highly probable that this speed can be maintained and exceeded in practical trials. It is quite another matter, however, whether Bavarian State Railways are suited for such abnormal velocities in ordinary service. Were this so, we should have long since heard of extraordinarily high speeds in the south and west German states. Already speeds of 90 miles per hour with a train of 138 tons (car load) have been attained, on a slightly rising gradient, by Maffei "Atlantic" type locomotives that were built for maximum speeds of only 75 miles per hour. Such engines were not in the high speed steam locomotive trials of March, 1904, but they exceeded for speed and tractive power the results obtained from other engines on the special Marienfelde to Zossen line, and, in fact, accomplished some of the fastest runs that had been made in Europe up to that period. The new engines resemble somewhat the 4-4-6 Thuile locomotive of 1900. All the constructive details are very fine; the work, in fact, approaches as near to motor-car practice as is permissible in railway engines. 

The new high-speed engine has four cylinders, compound, with the low-pressure outside as usual, and all bolted together in one transverse line. There is one driving axle only, and the driving mechanism is nearly perfectly balanced. The small counterweights in the driving and coupled wheels show to what extent the revolving masses have been made self-balancing. The fine proportions of the driving and coupling rods contribute to the elimination of disturbing forces.

The piston valves are of large size, and have the great length usual with double-ported distributors. At each end of the low-pressure valves are two small cylindrical valves connected with the expansion gear, and these open when the cut-off exceeds 70 per cent of piston stroke, as in starting, and thus admit high pressure steam to the low-pressure valve chests until the engine has been geared up to less than 70 per cent. There is one set only of valve gears for four valves, and no intercepting valve is introduced.

Bar frames have been employed for reasons of economy in weight. Incidentally these frames permit ready access to all working parts placed between them. Even the coupling rod on the opposite side of the engine is also discernible through the driving wheels.

All parts of the engine presenting broad surfaces at right angles to the engine have been clothed in such a way that they cleave the air, and reduce the head resistance when traveling at high speed. Careful experiments on the Continent and elsewhere have proved the real saving of power thus realized. It may be added here that the engine is of great length-45 feet 2 inches-with a height to the boiler center of about 9 feet, and a total height of 15 feet.

The high-pressure cylinders have a greater volume than those of any other European locomotive, including the new Belgian engines, but the boiler pressure of the 4-4-4 engines has been reduced to 30 pounds less than that of the most recent saturated-steam locomotives of the Bavarian railways. The ratio of volumes! high pressure to low-pressure cylinders, has, at the same time, been decreased. The driving wheels are the largest that have yet been employed for four-cylinder compounds on the European continent. The principal object in the design is high speed with a light load, for which the 32 tons maximum adhesive power will  be fully adequate. Compounding and superheating are introduced as contributing to this end, while the total mechanical efficiency is increased at the cost of some few tons of weight extra, which has, in large part, been compensated for in the general design of the locomotive.

This engine, the first of a new series, was designed and built by the firm of J. A. Maffei at the English Garden Works, near Munich.