I give this film six stars, but it will likely be either a five or eight star movie for you depending on what interests you. 1930's "Other Mens' Women" was a love triangle set around the railroad yards. Conversely, "Danger Lights" is almost a documentary on railroads as they existed in 1930 with a love triangle thrown in to frame the railroad footage. It's almost like the filmmakers knew they were really documenting history more than filming a love story. You've got footage of a tug of war between two steam locomotives, actual documentary footage of the activities in the Miles City railroad yard, and to top it all off is the only footage of a dynamometer car from the steam railroad era. Since the emphasis is on the technology, you'd think this film would have the awkward dialogue of the early talkie era, but you'd be wrong. The actors behave and speak quite naturally. To top it all off, you're rewarded with a very early talking screen appearance by Jean Arthur who will become one of the great comic stars of the 1930's.
As for the love triangle, it's very formulaic. Railroad division chief Dan Thorn (Louis Wolheim) decides to help out drifter Larry Doyle (Robert Armstrong) with a job as fireman. Unfortunately for Thorn, it's basically love at first sight between his fiancé Mary Ryan and Larry. Dan and Mary have had an understanding for years. On Dan's part it's true love, but on Mary's part it has largely been gratitude for Dan supporting herself and her father after he was injured on the job. Dan doesn't notice what's going on between Mary and Larry because in actuality there is another woman in his life too - the railroad he runs.
If the love story doesn't impress, the imagery certainly will. Lots of time is spent showing men battling both machine and the elements trying to keep the trains going. Plus there's a pride in what they do that almost makes them all a part of the railroad themselves.
