In 1905, the Uncanoonuc Incline Railway & Development Company began constructing the Uncanoonuc Incline Railway. The first part of the line was built as a two and a half mile conventional streetcar line. The line branched off the Manchester Street Railway at Shirley Junction and went to the base of the south mountain. A streetcar ride from Shirley Junction to the base station took 15 minutes, but since the conventional streetcar line was on a 4.5 percent incline, it took only 6 minutes to return to Shirley Junction. At the base was a transfer point between the conventional line to the incline. It wasn't until June 8, 1907 when the railway opened. The ruling grade of the incline was a grand 35% and the running time was five minutes. Equipment on the incline was two open cars that were connected by a steel cable and were operated like counterbalances. Each incline car was equipped with two 40-horsepower motors and carried a motorman and conductor.

Even though the Uncanoonuc Incline Railway branched off the Manchester Street Railway, there was never and through service from downtown Manchester to the mountain. All passengers had to transfer at Shirley Junction. Streetcars from Massachusetts and other parts of New Hampshire did occasionally run from their respective areas to the base of the mountain for special excursions. One big event that is remembered in history is when sixteen streetcars of an excursion from the Boston & Northern Street Railway made their way to New Hampshire. Originally the Boston & Northern had planned only six cars, but 600 visitors ended up arriving to the mountain. Because of the restraints of the power station that Uncanoonuc used, it could only allow one car up to the mountain at a time from Shirley Junction.

In the 1930s, drastic changes took place on the mountain. The pavilion that was built on the summit of the mountain to replace the hotel was destroyed by fire in 1930. The operation of the incline railway did not cease, as its schedule of May to October changed to the winter season as skiing became the new attraction on the mountain. Uncanoonuc became the first ski area to have a ski lift that wasn't a rope tow in New England.

The conventional trolley line to Uncanoonuc remained in service until 1938 when the line was abandoned, but the incline continued to operate until the 1940s. In 1941, a forest fire torched approximately 500 feet of the track and the steel cable. Even though the incline was being used to shuttle skiers to the summit, there was no effort to rebuilt the incline after the fire. Shortly after the fire, the remaining track was torn up and the cars junked. Amazingly, a bench was saved from one of the incline cars. This bench has since found its way to the Seashore Trolley Museum, where it is in storage.

Today at Uncanoonuc one can find traces of the railway with remnants of hardware scattered along the incline. Perhaps one of the more interesting monuments besides that of the various foundations left behind, are the bodies of four Manchester "Rapids" at the base of the mountain. When the Manchester Street Railway ceased using the interurban cars, five of them were left at Uncanoonuc, four at the base and one on the summit. The car on the summit was stripped by members of the Seashore Trolley Museum for restoration of Manchester & Nashua St. Ry. #4. The other four cars at the base are there today, serving at residences.