The main attraction of northwestern Montana’s Glacier National Park is the east-west drive across the Continental Divide on Going-to-the-Sun Road.

Many experienced windshield tourists consider this remarkable road – which opened for business 78 years ago this summer and was one of the great engineering feats of its time – the single best scenic mountain drive in the 48-state U.S.

Visitors normally undertake the 50-mile drive in their private vehicles, enjoying the scenic turnouts, charismatic wildlife, wayside exhibits, and magnificent views from the road. However, the park’s little red 1930s-era “gear jammer” tour buses offer a superb way for visitors to just sit back and enjoy the trip. The gear jammers, which are listed on the National Register of Historic Places, run on clean-burning propane fuel.

While mornings can be cold in Glacier even in summer, the jammers come equipped with heavy wool blankets for passengers.