When did the USMT arrive at Gettysburg?

Immediately after the battle, operators Edwards and E.A. Hall were sent to Hanover, PA., seventeen miles north of Gettysburg, to open an office on the line belonging to the railroad company, which was run into General Schenck's head-quarters office, at Baltimore, from whence it connected with the War Department. The operators arrived about five, A.M., of the fourth, and finding the doors of the station fastended by gread padlocks, they broke open the window with stones and clambered in. While in the act of connecting their instrument, the Superintendent of the road, Mr. Eichelbergher, came running to the depot with fifteen or twenty men, and demanded of the operators, in a loud voice, "By what authority do you break into this depot?" Edwards presented a blank U.S.M.T. evelope, as being the best evidence he had of his authority, but that proved enough. As the Confederate States troops had torn down the line running thence to Gettysburg, strenuous efforts were made to rebuild it, which was first done temporarily -- the repairers using for the purpose scraps of stove-pipe and odd pieces of wire. These were fastened to the nexts of old bottles that were placed int the crotches of trees, where they held and insulated the line. Edwards started from Hanover with the builders, but on reaching a small stream near Gettysburg, where a bridge had been burned, it was found that the wire had shrunk so that the two ends could not be brought together. In hunting around, Edwards discovered in the stream some old soda bottles and an iron rail. The later was propped with those of the rail. Thus was communication first established between Gettysburg and the North, after being cut by Stuart. Several operators remained at Gettysburg some time, receiving and transmitting a great number of messages to and from the wounded in hospitals there.

Signal Corps movement into Gettysburg:

Myers signaling system was catapulted into use at the Battle of Gettysburg. General Lee had invaded northern soil in June 1863. His Potomac crossing was relayed by flag system to the War Department. General Joseph Hooker resigned under fire on June 28. General George Meade (of NSA grounds fame) took over command of the Army of the Potomac. His headquarters were at Taneytown, MD. Startling news came via signalmen on July 1. A skirmish on the Maryland border indicated that General Buford was facing a major force not in Maryland but in Pennsylvania. Lee was himself in command at Gettysburg. Signalmen of each army unit sent out calls for help. Reinforcements from dozens of units several miles away were committed to the fray. By July 1, 73,000 gray and 88,000 blue met in one of history's most decisive battles. Rarely, if at all, do textbooks even hint that the secret message system of flags affected these history changing events. Yet the crucial sightings by Union observers directly tipped the scales against Lee's best tactics. The most famous incident was when Captain Castle on Cemetery Ridge, refused to submit to Confederate artillery barrage as General George Pickett charged the "thin blue line", used a wooden pole and a bedsheet to make a makeshift flag to alert Union forces under General Meade who ordered counter- measures. Pickett's charge was stopped short of breaching the Union lines. General Lee's gamble failed. Previously disregarded flagmen enabled George Meade to enter the shrine of heros. [BLUE], [ANNA], [MYER], [NIBL], [TRAD], [WRIX], [KAHN]