antique and all original nineteenth century brass signal padlock without key, manufactured for use in the rock island railroad system, out of rock island, illinois. the heavy metal lock is incised on the front "rock / island / lines / signal" and would have been used for securing a "signal" box. it features surface wear or patination typical of its age and date of manufacture. rock island railroad system was first organized in 1845 at a meeting of civic leaders at rock island, illinois. as a result of the increasing migration to the west, they aimed to build a railroad from la salle, illinois to rock island, to provide an overland link between the mississippi and illinois rivers. the rock island and la salle railroad company was incorporated in february 1847, and in soon after the organizers then petitioned the legislature to build the railroad all the way to chicago. in february 1851 the charter was approved and the name was changed to the chicago and rock island railroad. on october 1, 1851 construction began at 22nd street, the southern limits of chicago and railroad construction officially begun. in a year the line was completed to joliet, 40 miles away. in october 1852, a locomotive first ran on the line, called the "rocket"; the trip took 2 hours and was cheered by thousands along the way, making the return trip as a back-up movement as there was yet no turning facility at joliet. throughout the 1850's the rails moved through morris, ottawa, la salle and bureau, connecting chicago with the mississippi river. the railroad continued to expand and in 1866 acquired two other lines to become the chicago, rock island and pacific railroad company. during its height, the lines stretched across the midwest connecting chicago with mineapolis, omaha, st. louis, and memphis, as well as reaching denver, dallas/fort worth, and galveston. at the peak of the railroad’s size it operated over 8,000 miles of track. while the rail comapny served most of the largest cities in the nation’s heartland, stretching between the midwest and southwest, it was unfortunately the most circuitous, allowing competitors with much more direct routes to outcompete the rock island for traffic (such as the union pacific and santa fe).