''Probably no railroad in the east has enjoyed more popularity with the model makers than this one . . . Once you have started to read this book, you'll have difficulty in letting it alone. The author is to be congratulated for giving us such a valuable and interesting history.''Railway and Locomotive Historical Society Bulletin Affectionately known as the ''Ma and Pa,'' the Maryland and Pennsylvania Railroad was one of the country's longest running and best known ''archaic'' railroads, holding on to steam locomotion and other outmoded technologies well into the twentieth century. Connecting Baltimore and York, the line had everything needed to endear itself to local residents and rail enthusiasts: picturesque equipment, marvelous scenery, antique passenger trains, handsome small-scale locomotives, and enough curves476for a railroad many times longer than its 77 miles. All this made the Ma and Pa one of the most popular prototypes for model railroaders, George Hilton notes, and thousands of miniature versions of the line became part of model railroads throughout the world. This new paperback edition of Hilton's classic history includes a new introduction and epilogue in which the author recalls the line's final years of service. He also comments on the continuing interest of modelers, enthusiasts, and all who fondly remember the Ma and Pa. ''George Hilton's affectionate yet complete and accurate account of Ma and Pa is at once all that the short line's host of admirers could ask as well as a model of How To Write Railroad History. Hilton can examine a balance sheet without forgetting the flanged drivers that generated its figures; to the past he can be sympathetic without letting the sentiment become sticky. In eight chapters he moves across the years from 3-foot beginnings to the road's World War I peak and beyond the lean times, amputation, and a 1960 I.C.C. refusal of an abandonment petition. His text is supported by a chronology, all-time engine and equipment rosters, employee timecard, maps, even a dispatcher's train sheet . . . The photo count exceeds 175 and these are supplemented by side and end elevation drawings of several locomotives and doodlebug 62.''Trains