Then they did so. They built the Union Pacific west from Omaha and the Central Pacific (now a part of Southern Pacific Lines) east from San Francisco. Today this is the central line across the continent and the story of its building is a story of heroic achievement. In 1868 they came to the flat, broad bed of Lake Bonneville. But Great Salt Lake lay in the center and barred the way. So they built the track around the lake to the north, as you may see by the map. A third of a century later there was much more business. Engines were five times as large. Freight cars would carry five times as much weight. Where once one train ran each way a day, now sometimes a dozen each way climbed over Promontory Mountain north of Great Salt Lake. Between Ogden and Lucin was a fine, level roadbed made by Lake Bonneville. 18 Only Great Salt Lake, thirty feet deep and thirty miles broad, lay in the way. And so every day trains were lifted in curves fifteen hundred and fifteen feet higher and carried forty-three miles farther than would be necessary if a road were built straight across the lake. So the Southern Pacific railroad men looked at the old grade over the mountain and then at the level way across Great Salt Lake and they said: "Let us build a cut-off, a straight, level line, over land, through water from Lucin to Ogden." And they did so. This is how it was done. Word was sent to the iron furnaces and the steel mills in the East. And presently they were busy at work smelting iron ore and shaping steel for a thousand carloads of heavy rails. Word came also to forests a thousand miles away in Oregon, California and Texas. It said that a trestle bridge twenty-three miles long was to be built. 19