The opening figure in the piano is a sort-of whoo-whoo of a train whistle and the rhythmic figure starting in m. 6 is supposed to be descriptive of a steam engine chugging along the track. Thomas H. Johnson, in his Introduction to Final Harvest, a collection of Dickinson poems, posits that Emily used dashes as a musical device and capital letters as a means of emphasis. He further writes that she deliberately fractured grammar to achieve special effects. I like to see it lap the Miles is testimony to Johnson's analysis and apparently celebrates that exciting form of transportation in the 19th Century, the railroad.