Big 10 Curve at Arvada, Colorado | Union Pacific Moffat Tunnel Subdivision

ABOUT THIS LIVESTREAM:
Virtual Railfan's live PTZ train camera at Arvada, Colorado, overlooks the stunning "Big 10 Curve" near Milepost 21 on the historic Union Pacific Moffat Tunnel Subdivision. This iconic S-shaped curve, built in 1902 by the Denver, Northwestern & Pacific Railway (DN&P), marks the dramatic transition from the Great Plains to the Front Range of the Rocky Mountains. The DN&P later evolved into the Denver & Salt Lake Railroad (D&SL), which was acquired by the Denver & Rio Grande Western Railroad in 1931, with the merger finalized in March 1947.

The Big 10 Curve earns its name from its two distinct sections: the "Big Ten Loop" and "Little Ten Loop," each featuring sharp 10-degree radius curves. Designed to manage a challenging 600-foot elevation gain over 2.85 miles — originally a steep 4% grade — the curve extends the route to 7 miles, reducing the gradient to a more manageable 2%. This ingenious design has made it a marvel of railroad engineering.

Located on Union Pacific's Moffat Tunnel Subdivision, Big 10 sees Union Pacific, BNSF (trackage rights), and Amtrak California Zephyr trains daily. The Rocky Mountaineer also operates several times weekly. The average daily train count is 12, with 10 freight and 2 Amtrak, but it may exceed 15 depending on overhead BNSF thru-traffic and the Union Pacific "Rocky" local. Big 10 is unique in that viewers can watch trains approach our camera for over 20 minutes, as our host provides a picturesque, unobstructed view of the valley below and the Denver skyline.

This camera captures the full spectacle of freight and passenger trains navigating one of North America's most iconic railroad curves. Whether you're a railfan tracking UP and BNSF operations or a casual viewer enjoying the dramatic mountain scenery, Big 10 offers extended train approaches and a window into the region's legendary railroad engineering heritage.