It expanded from its Golden–Denver line to form a crucial link connecting Colorado with the transcontinental railroad and the national rail network.

The company built the first rail lines up connecting historic Colorado mining communities such as Black Hawk, Central City, and Idaho Springs.

Loveland and his partners desired to build a 4 ft 8+1⁄2 in (1,435 mm) standard gauge railroad up Clear Creek Canyon to Central City and other mining centers, and to connect to nearby Denver and Boulder.

The following year, in June 1867, the company was reorganized; Union Pacific investors were in control, but provided no funds for construction.

By the following year, the success of the Denver Pacific investors in persuading the United States Congress to grant them land allowing them to construct a line throughout the South Platte River valley to Cheyenne made it evident that Denver would prevail over Golden.

By the following September, 150 men were at work in the mountains west of Golden to extend the line to the mining communities.

The see-saw battle for control of the company between local and outside interests continued during the expansion of its lines into the mountains.

By the spring of 1873, Jay Gould and other Union Pacific investors had contributed a large financial stake in the railroad, but the company was still controlled by Loveland.

The nationwide financial collapse that began later that year practically halted new construction on the company lines, instigating a period of legal struggles for control of the near-bankrupt enterprise.

The following month, the company board of directors repudiated the agreement by voiding the votes of the Union Pacific proxies on a technicality.