2431590 - DENVER & RIO GRANDE LEGACY H7 2-8-8-2 #3605

In need of larger power but strapped with smaller tunnels, the Chesapeake and Ohio ordered a relatively novel group of 25 simple-expansion 2-8-8-2 locomotives from Alco in 1923. Compound Mallet locomotives, which used steam exhausted from the first pair of pistons to power a second, were nothing new on the C&O or elsewhere. But using steam directly from the boiler to power all four pistons had only been tried a few times - and not on a production locomotive. The single expansion offered more power and reduced the size of the large pistons needed in a Mallet. But it also required a larger boiler to produce enough steam for what was essentially, two steam locomotives. Keeping this within tight clearances lead to the locomotives' other distinctive feature - a smokebox crowded with appliances like air pumps, feedwater heater and even the bell which couldn't fit anywhere else and make it through a tunnel intact. It became a C&O standard on many locomotives for years to come. Althoug