What railroad for which Oakes Ames is credit as being the single most important influence in building was caught up in the  Crédit Mobilier scandal?
Crédit Mobilier of America scandal The Crédit Mobilier scandal of 1867, which came to public attention in 1872, involved the Union Pacific Rail Road and the Crédit Mobilier of America construction company in the building of the eastern portion of the First Transcontinental Railroad. The scandal was in two parts. The construction company charged the railroad far higher rates than usual, and cash and $9 million in discounted stock were given as bribes to 15 powerful Washington politicians, including the Vice-President, the Secretary of the Treasury, four senators, and the Speaker and other members of the House.
Denver and New Orleans Railroad The Denver and New Orleans Railroad (D&NO) was a railroad in Colorado started by Colorado Governor John Evans, along with railroad entrepreneur David Moffat and other associates in 1881. Originally chartered to build a railroad from Denver, Colorado to the Gulf of Mexico, the charter was later changed instead connect southward to the Fort Worth and Denver City Railway which was building northwest from Fort Worth, Texas.