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?
Oakes Ames Oakes Ames (January 10, 1804 – May 8, 1873) was an American manufacturer, capitalist, and member of the United States House of Representatives from Massachusetts. As a congressman, he is credited by many historians as being the single most important influence in the building of the Union Pacific portion of the transcontinental railroad. He is also noted for the subsequent scandal that alleged the improper sale of stock of the railroad's construction company.
IANR Railroad Underpass The IANR Railroad Underpass is a historic structure located in Cedar Rapids, Iowa, United States. It carried railroad tracks for 24 ft over Ely Road. The railroad probably built this stone arch bridge, which was completed in 1887. This kind of structure became more popular in the late 19th century as a railroad bridge because it was more durable than metal truss bridges, and they "projected a refined and sophisticated image." It features a semi-circular arch, a beltcourse, coursed-ashlar masonry, stepped wing walls that are flared, a parapet with projecting coping, and an elongated keystone with the date "1887" carved on it. The bridge was listed on the National Register of Historic Places in 1998. It now carries the Cedar River Recreation Trail over the street.