Cliicigo uii:iig otlisr curiosftleg peculiar to her, is shortly to liave the largest and fasie.-i passenger locomÖtlve ever conatructeü, wlitch will surpass In everywny anything liillierto atteinpted in ita way. Thli wonderfnl engine, designed by G. 8. Strong, of New York, has just been completad in Boston for the Atcliison, Topeka & Santa Fe railroad, and when shippecl west will be nsed for hauling the vestibuled train between Chicago and Fort Madisnn. It has a doublé tire-box, with a lieating surface of 1.654 square feet, posessing 300 iiues. lts cylinder is 19x24 Inches, and with drivlng-wheels eighty inches in diameter ia expected to haul ten cars over an ordinary road at the rate of eighty miles an hour. All the vvhccls are of paper, with steel tires. A new feature introduced into the cOQStrnctlon is the steam pump, whicli so worksthat a great part of the exhausted steam is putnped back and serves to heat the water In the tank before lt goes into tbe boiler, tliereby lavlng a great deal of fuel. Anothcr cconomy in fuel is the work of a large combustión chamber in conncction with the firebox, whicli br.rnsupall tliesmoke and gas instead of lettinfr it escape by the stack. The boiler, instead of being built with staybolts, is licavily corrugated on tbe insiile. The tirst thing observable is the singular posilion of the engineei's c;:b, irhïcli i perched up on top of tlie boiler about the center and is occupied by the engineer alone, as another cab built behind tlie boiler is provided for the tiifin in. In each is a perfect system of gauges to keep Ir.ick of the steam power. The engine alone will we.igh fifty-five tons. The engineer who was selected to sit up in the new cub and run this new coutrivanee is G. S. McKee, ot Chicago. He is in Boston at present, and is being made perlectly acquainted with all its nieohanism. He expresses dulight over the m ichine and is most anxioua to have her In service. It bas been named the A. G. Darwin, after the president of the company designing it, und it will start for Chicago nest week.