Sr. Louis, June 9. - The first locomotive, with three passenger coaches eontaining a number of invited guests and representativas if the, press, crossed the bridge this evening to test the track, which has just been laid. Sheruian, who was of the party, drove tho last spike conneoting the bridge track with that of the Vandalia Eailroad, Maj. Simpson, General Superintendent of that road, also officiating. The train was run over the bridge several times and about a third of the way into ths tunnel on this sido oí the river. On backing up the last time the train was halted on the center span of the bridge, und tbe guests drank the bealth of Capt. Jumes B. E;ids, ohief engineer, and that of the directora and stockholders of the bridge company. Geil. Sheruian and others made brief and appropriate speeches, and the oocasion was one of inuch congratularon and pleasure. Engineers, several of whoui oonuectad with roads centering here, were present, and were delighted with the structure, which eave no token of ness. Not tbe slightest jar was peroeptible. A regular scientific testinf of the bridge, with immense weights and various ! appliauce8 kuown to the profession, will take place in a few days in the presanoe and under the direotion of somf of the most uoted engineers, in the country. Iraffio on the upper roadway of the bridge is already assuming large diirenlions.