In years past the Southern Railway System was well known for its magnificent fleet of steam passenger locomotives. Now diesels have banished the old steam giants from the Southern's rails-but they had to bring their own steam along to make a go of it. Even a diesel enthusiast has to admit that steam still plays a major role in keeping passengers comfortable.

One of the problems to be met in replacing steam power with diesel locomotives in passenger service was the necessity for persuading a diesel locomotive to produce steam for heating passenger cars. Without a plentiful supply of steam the shiniest streamliner would be an ice .box in the winter and an oven beneath the summer sun.

Harold E. Adair, car inspector, Atlanta. Terminal Company, couples the steam line from the diesel locomotive to the first car of the northbound "Crescent."

Heart of the modern diesel passenger train heating system is an oil-fired steam generator little larger, than a home heating furnace. It is installed in the engine room of the diesel locomotive unit. Fueled with oil from the diesel's fuel tanks and supplied with water pumped from a special storage tank, the flash-type boiler will build up 200 pounds of pressure in two minutes from a cold start and maintain it at its full capacity as long as fuel and water are supplied and the pumps hold out.

The steam generators used on the Southern come in numerous styles and sizes (we use three different types on our 2,000 horsepower passenger units, 1,500 horsepower combination freight and passenger units and road switchers) but the basic operation is much the same.

Making adjustments in the heating system of a bedroom in one of the all-room Pullman cars of "The Crescent" is part of the work of George Bohlen, Pullman Company electrician

Atomized diesel oil injected into the boiler and mixed with air from the blower is ignited by a spark, which is produced by a spark plug similar to those used in an automobile, sending a hot flame around hundreds of feet of coiled steel tubing. Water being continuously pumped into the tubes is instantly heated into steam which is fed into a pipeline running the length of the train beneath the cars-the main artery of the heating system.

Once the generator is switched on, automatic controls set the pace for the production of steam to supply the train line. Steam is made almost instantaneously as needed; there is no reservoir of heated water under pressure and there are numerous mechanical safe- guards to the prOp8r operation of the steam generator.

Connecting hose to flush out steam generator coils with water, acid and soda in that order: (front to rear) H. J. Landers, pipefitter apprentice ;. L. A. Bennett, pipefitter, and T. J. Still, pipe fitter helper, at the Atlanta diesel shop.

From car to car the steam line is connected through carefully-machined, flexible metal joints. that have to fit tightly enough to hold 250 pounds of steam pressure yet be easy to disconnect or connect when cars are .cut out or switched into the train.

On the underside of each car, this pipeline of high pressure steam is connected to automatic pressure regulators that reduce the pressure to three to eight pounds. These feed the steam into valves that admit it to car radiators.

During shop check-up C. B. Householder, boilermaker at Atlanta, removes the smoke hood to inspect the interior of a steam generator 'in a locomotive,

Train heating involves many problems not found in heating a home. Racing down the track at top speed a streamliner is, in effect, breasting a 70-mile-an-hour gale of its own making. At a station stop the artificial tempest has died down and even thin winter sunlight tends to warm a standing car. Moments later the air is again streaming past the rushing train, carrying some of the car's heat away with it.

Heat requirements vary widely and rapidly for these reasons and, also, because a train, unlike a house, doesn't always stay in one climate.

HC-50, the Southern's heater car, is a partner of freight-type diesels pressed into passenger service. The car contains two steam generators and necessary auxiliary equipment.

The "New Royal Palm," for example, speeds from Cincinnati's winter snow and sleet to Florida sunshine in 24 hours. In all-room cars the problem is further complicated by individual passenger preferences in temperature.

A mercury-filled tube about the shape and size of an ordinary clinical thermometer provides "weather" on demand. Sensitive to changes of as little as three- tenths of a degree in temperature, it is the heart of a thermostat that takes all the guesswork out of car heating.

The number of such thermostats in a car varies with the type of equipment. Coaches usually have six-one for radiators along the floor on each side, one in the passageway at each end, one in each lounge and one controlling the overhead heat-although there is a simpler system that employs only one thermostat to a coach. Room cars have a separate radiator and thermostat in each room, sometimes as many as 20 in a single car. Each occupant can set his own temperature level.

Working on steam generators at Atlanta diesel shop W. P. Futch, pipefitter (left), and L. E. W. Meyberg, pipefitter apprentice, place coil pads in a steam generator.

When the mercury in the thermostat drops below the comfortable temperature setting (usually placed at 73 to 76 degrees) electrical contact is broken between the falling column of mercury and a hair-thin platinum wire, causing the steam valve on the radiator it controls to open and admit steam to the radiator.

At the same time a pulse of electric current travels through a heating wire in the thermostat tube, causing the mercury to rise, make contact again with the wire and shut off the steam valve. In this fashion steam is fed into radiators a little at a time to keep the car comfortably warm.

The heating system is designed so that condensed steam will drain out to the ground and not freeze in the pipes when cars are standing in coach yards in cold weather. Usually, however, steam from the coach yard line is connected to the cars and stand-by thermostats keep the temperature at about 60 degrees so that the cars can be heated quickly to be placed in service.

Meyberg (left) helps I. G. P. Holton, pipefitter, hook up the overhead crane to a steam generator to lift it and " place' it in a diesel locomotive.

A locker at the end of each passenger car contains the electrical control panel whose relays and switches control the available steam. Here an employee operates certain switches to set the whole heating or cooling system in operation.

Yes, cooling depends on steam as well. Oddly enough, the steam generator works harder in summer than in winter. A large percentage of the Southern's passenger cars use the steam-injector type of cooling and that requires more steam than car heating.

S. M. Waddell, boiler-maker, guides the steam generator down as the big over- head crane at Atlanta diesel shop lowers the generator into place.

For year-round comfort on passenger trains the Southern depends on thorough maintenance. At shops which service passenger diesels, steam generators get the same regular and detailed attention given to all other parts of a diesel locomotive in the railway's maintenance program.

Daily, or after each run, there are 25 items to be checked in steam generator maintenance and the work increases in scope on weekly, monthly, quarterly, semiannual and annual inspections.

Heating equipment in cars is checked regularly at terminals and some intermediate stations. Major repairs-and new installations when required-are made at Hayne Car Shop in Spartanburg.

A. J. Karter, machinist at the Southern's Alexandria, Va., diesel shop, makes adjustments to a steam generator.

Many descriptions have been used to highlight the powerful performance of a steam generator

For example, its boiler gives off as much heat as a fighter plane's jet engine and it will produce enough steam to heat 96 five-room houses in zero weather. But, first and most important to us, is that it will produce enough steam to heat or cool a train of cars and keep the Southern's passengers comfortably warm or cool as outside temperatures demand.