I have blogged about a railroad barge (Feb 15, 2014) that took trains across the Mississippi River: The Mastodon.
This ferry boat took trains from one side of the Carquinez Straight, east of San Franciso, to other side; from Benicia to Martinez, California and back in less that 10 minutes. "The Solano" was named after one of the counties in California where it operated, the side of the straight in which Benicia sits. It worked toward the very end of the Transcontinental Railroad route; after the crossing it was a short trip to Oakland. At its building, it was the largest railroad barge in the world.
It was built in 1879 by the Central Pacific Railroad to get the trains across a water barrier that stood between Council Bluffs, Iowa and the end of the line. The axis of the slip on each side of the straits coincided nearly with the direction of the current, pointing on the Port Costa side up, and on the Benicia side down stream, so as to facilitate entering the slips. The distance across was one mile; the whole time consumed in transit was nine minutes, including starting and stopping.
It was a very large ship: Deck Length = 424 feet; Beam at center = 116 feet; Height at center = 18 feet 5 inches. The draft when empty was only five and a half feet; when loaded it was a whole six and half feet. The tonnage was listed at just over 3500 tonnes. The engines that worked the paddle wheels had a 5 ft diameter bore with a stroke of 11 feet. The paddle wheels themselves were 30 feet in diameter, 30 inches wide and they had 24 buckets each. There were 8 boilers on board. They were 7 feet in diameter by 28 feet long; they each contained 143 4 inch tubes so that there was almost 20,000 square feet of heating surface within the boilers. The whole combination generated 2,000 horse power.
By the time this picture was taken, the Southern Pacific had purchased the Central Pacific RR so the title on the card says that it is "S.P. Co.'s Ferryboat 'Solano'". It was the largest ferry boat in the world until its sister, the "Contra Costa" was built in 1914. Both ferries operated until 1930.