If the rail is 56 lb/yard, then the total rail weight is about 175 thousand tons (about a hundred tons of rail per mile).
See comments regarding the role of the government in financing the transcontinental railroad. The bonds were sold at par in New York, then transferred to San Francisco where they were converted to cash/gold.The ties varied in size, some as long as 10 feet and some as large as 8"x10" in size, depending if the track was being laid in the mountains or the deserts, on heavy or gentle grades, on curves or tangents (straight track). At one time the Central Pacific had as many as 25 Saw Mills in Truckee just milling lumber for the railroad which required as many as 40 trains to supply the front withties and timber– and they just managed to keep up with the track laying forces.Entire forests were cut back for miles from the line, some taking a hundred years or more to recover.About 200,000 net tons of iron total were used just for building the railroad from Omaha to Sacramento [at 2000 lbs/net ton, the modern useage, also called the short ton; the metric ton = 1000 kg ].
Details, at 60 lb/yard (per single rail) single track from Omaha to Sacramento: 1776 miles x 60 lb/yard x 5280 feet/mile x 1/3 yards/feet x 2 rails x 1/2000 ton/lb = (1776*60*5280*2)/(3*2000) = 187,546 tons of iron.All rail ordered for the Central Pacific Railroad was by the metric ton, 2240 pounds per ton.