The New Haven Line to Fitchburg is the Agricultural Branch RR, a portion of the Worcester & Fitchburg and the Framingham Branch of the Boston & Worcester. The Boston, Clinton & Fitchburg took over the property and then it fell into Old Colony hands. The Agricultural originally served as an outlet for area farm towns. The push to cobble together a through route from Fitchburg to the southeast was fueled by the impending completion of a through route trunk line via the Hoosac Tunnel. The other trunk line routes were the Boston & Albany and Boston, Hartford & Erie. The Old Colony got into the picture because it was crammed into a corner of southeastern Massachusetts and pretty much had to interchange traffic to and from the West at Boston. (A good portion of U. S. railroading has always been concentrated to West-East traffic.) A route from New Bedford to Fitchburg opened up interchanges with the Boston & Albany at Framingham and the Fitchburg at Fitchburg. However, the Fitchburg could interchange southeastern New England traffic at Worcester via its Boston, Barre & Gardner. I worked for the Boston & Maine, 1968-86 and for a time did daily interchange reports. Very little traffic was interchanged with the New Haven, later Penn Central, at either Fitchburg or Clinton. The route probably survived until the early 1930s on passenger traffic and local freight. Many of those towns between Fitchburg and Framingham, except Marlboro did not have another direct rail line to Boston and in pre-trolley or auto days, those towns had pretty good sized populations which would generate town to town riding. In 1912 there was a period where a number of through passenger trains ran from Fitchburg and Marlboro into South Station via Framingham. The comprehensive through schedule lasted only for months. However, there was one through train for a number of years and timetables showed good connections to South Station down to the end of passenger service, about 1937. By the 1940s, local freight traffic was declining, especially coal for home heating. (Find where Summit station was in Bolton; there was a coal trestle there.) Then something new came along, plastics. Leominster had a number of companies working on plastics and chemical generally came in by rail.