Calvert Holt Sees It Through

The Model Engineer and Practical Electrician

October 20, 1932

Shops Shed & Road

A Column of "Live Steam."

By "L.B.S.C."



Soon after that never-forgotten and ever-regretted Sunday night when my wife and I said good-bye to friends Calvert Holt and Joe Lozier at the New York pier, the former wrote that he was just about to start on a 7-1/4 inch Pennsylvania K.4 Pacific. Last week (time of writing) I had a long letter and several pictures, two of which are reproduced here, to say the job was through, and the engine a perfect success. It has been a pretty long and arduous task; but I guess you'll all agree it was worth while, and join in hearty congratulations to our worthy brother over the pond, and his assistant, on the result of 3,200 hours' "hard labour." A little heftier job than the "Silver Rocket"!

The type of engine is pretty well known, so I need only point out a few special features. The wheels have "scale" treads and flanges as she is going to work on a "scale" road, and the drivers have proper steel tyres shrunk on. Ball bearings are fitted to the driving, coupled and trailing axles. The cylinders are "scale" size, 3 in. bore and 3-1/2 in. stroke, with piston valves having a bore of 1-5/16 in., and 7/8 in. travel in full gear, giving a cut-off of 70 per cent., the lap being 5/32 in. and the lead 1/32 in. These valves have four cast-iron rings on each. The Walschaert valve gear is an exact copy of the gear on the full-sized engine. The cylinders are lubricated by a mechanical oil pump made like my small water pumps but operated by a ratchet drive, which can be graduated from one stroke in eight revolutions to one in forty.

The boiler was made by our old friend Mr. Goodhand, who, although he had never seen a boiler of the peculiar shape of the P.R.R. before, nevertheless made a fine job of this one. The neat way in which he flanged out the end of the barrel to match the contour of the Belpaire firebox, to save making another extra joint, was worthy of commendation. I saw the boiler tested to 300 lb. water and 150 lb. steam before bringing it away for delivery to the shipping agents (Messrs. Rosenberg, Loewe and Co., Ltd.), who packed and delivered it to friend Holt without a scratch. The boiler is all copper, mostly 1/4 in. thick, well riveted and stayed, most of the joints being caulked in regular boiler-making fashion (no "soft tommy") and the combustion chamber was all brazed up by aid of an oxy-acetylene blowpipe. It is fed by two injectors made by friend Holt to my pattern, and also by a duplex donkey pump, made by Frank Birch to the Fayette design but much larger. This works champion, and with 80 lb. on the steam cylinders will pump up to a test pressure of 220 lb., so it puts the water in the boiler all right. The boiler fittings include two pop safety valves with 3/8 in. balls, the valves being made as described in these notes, and shutting down with a variation of 2 lb. only. The boiler will make far more steam than required, and keeps popping off all the time the engine is running; and will even make steam against both injectors and the pump, if the fire is bright.

All details on the engine are, as near as possible, same as on big sister, and everything works. Full brake gear is fitted, which at present is operated by two steam cylinders 1-5/32 in. bore and 1 in. stroke, with a 5 to 1 leverage, and is powerful enough to pull the engine up with throttle open in 25 ft. run. Evidently brother Holt remembers a certain little episode on the Toonerville--I shan't forget it anyway! The air-brake system is also being fitted, as described in these notes for smaller engines, and the air pump for this will be a duplex Westinghouse type, but simple instead of compound. The springing follows full-size practice, the driving springs each having sixteen plates 3/4 in. wide. The headlight has a 10 c.p. bulb in it, and the marker lights are fitted with correct coloured lenses as well as a bulb.

Although the boiler holds 7-1/2 gallons of water, it has actually steamed up from all cold in 12 minutes, although the usual time is about 20. The blast is sharp, and the engine keeps even beats when running with the lever one notch off mid-gear. She has, at time of writing, only been tried on a temporary line composed of regular "contractors" rails, as you can see in the picture; but even this has given some idea of what "Miss Bay Shore" (her proper name--but friend Holt calls her "Leaping Lena"!) will do when she gets on a road a mile or so long, like the Toonerville. Here are a few of the principal dimensions:




 * Height: 22 in.
 * Width: 15 in.
 * Length: 73 in.
 * Wheels
 * Bogie: 4-1/2in.
 * Drivers: 10 in.
 * Trailers: 6-1/4in.
 * Coupled wheelbase: 20-3/4 in.
 * Cylinders
 * 3 in. bore
 * 3-1/2 in. stroke
 * 1-5/16 in. piston valves having 7/8 in. travel
 * Boiler:
 * Length: 5 ft.
 * Diameter of barrel: 10-1/2 in.
 * Six 1 in. superheater flues
 * Twenty 3/4 in. tubes, all 34 in. long.
 * Working pressure: 96 lb.
 * Firebox: 17-1/2 in. by 9-1/2in.
 * Combustion chamber: 8 in. long
 * Weight full: 375 lb.
 * Total weight of engine only, in working order: 1,125 lb.

Tender runs on two four-wheel trucks with ball bearings and spiral springs; the body is made from 16 gauge sheet brass; the tank holds 20 gallons of water, the bunker 25 lb. of coal, and a seat for the driver (over the pond they call him the engineer) is fitted over the coal space. What the whole bag of tricks will shift from a dead stand on the level road, goodness only knows; but she has started from rest with a load of seven adults, on a grade of one in twelve, and on a 75 ft. radius curve at that. To those of us who have had practical experience of the way in which even a 1 in 100 bank takes it out of "big sister." it denotes exceptional power, with ability to hold the road without slipping.