Fortunately, the man in charge of the office, a Scotchman by the name of James Reid, took a liking to the Scotch lad and began to help him by teaching him telegraphy. Accordingly, during the leisure moments when Andie had no messages to deliver he studied so diligently that in a remarkably short time he became a skillful telegraph operator. At this time his father died, leaving the support of the family to Andie. To support them he must earn more money, and so he left his job as messenger boy to become a telegraph operator on the Pennsylvania railroad. While thus engaged as an operator he invented a system of train dispatching that, each year, saved the company thousands of dollars. This invention attracted the attention of the railroad officials to young Carnegie, and he was made private secretary to Colonel Scott, vice-president of the road, and a little later was made superintendent of the Western division of the Pennsylvania railroad, all before he was thirty years of age. It was while he was superintendent of the railroad that Mr. Woodruff, the inventor of the sleeping car, came to him with the invention. Mr. Carnegie listened to a description of the proposed cars. He saw that the idea was good and adopted it at once. Thus it was that on Mr. Carnegie's division of the Pennsylvania railroad the first sleeping cars in the United States were run. Prior to this time all the railroad bridges had been made of wood; but it occurred to Carnegie that bridges should be made of steel, rather than wood. Accordingly, he organized the Keystone Bridge Company that built the first steel bridge across the Ohio River. As the bridge business grew, Mr. Carnegie decided that he could make more money by making his own steel for the bridges. To do this he organized a company and built the Union Iron Mills. So profitable were these mills that in a short time he purchased the Edgar Thompson Steel Rail Mill and the Homestead Steel Works. Gradually his business grew until in 1901, when he retired, his payroll exceeded eighteen million dollars a year, and he received two hundred and fifty millions for his share of the business. But, I hear you ask, "How could he earn so much money? How did he get the money to start these great enterprises?" From the first he was economical and saved every penny possible; and fortunately for him his investments were always profitable, as the following examples will show. When he was a telegraph operator, his friend, Mr. Scott, urged him to buy ten shares in the Adams Express Company for six hundred dollars. As Mr. Carnegie was able to get together but five hundred dollars, Mr. Scott lent him the extra hundred, and the investment was made. Soon these shares were yielding large dividends, which Mr. Carnegie carefully saved.