The following information is for those of our ranks who are new to the hobby and have seen these terms and classifications mentioned and wondered what they meant. They are presented here from Model Railroader's CYCLOPEDIA - Volume I Steam Locomotives edited by one of the great masters of the hobby, Linn H. Wescott. If you like to model the steam era, this book is a must for your library. Steam Locomotive Names and Types All-Purpose Locos (early) 4-4-0 Eight-Wheeler, American or American Standard 4-6-0 Ten-Wheeler 4-8-0 Twelve-Wheeler 4-10-0 Mastodon or Gobernador Freight Locos 2-6-0 Mogul (also passenger) 2-8-0 Consolidation 2-10-0 Decapod 2-6-2 Prairie (also passenger) 2-8-2 Mikado (Mike), MacArthur 2-10-2 Santa-Fe 2-8-4 Berkshire 2-10-4 Texas Passenger & All-Purpose Locos 2-4-2 Columbia (passenger) 4-4-2 Atlantic (passenger) 4-6-2 Pacific (passenger) 4-8-2 Mountain (passenger) 4-8-2 Mohawk (freight) 4-10-2 Overland, Southern Pacific (freight) 4-12-2 Union Pacific (freight) 4-4-4 (freight) 4-6-4 Hudson, Baltic (passenger) 4-8-4 Northern, Greenbrier, Pocono, Niagara General Service or Dixie (passenger, freight, dual) Switcher Locos 0-4-0 Four-Coupled 0-6-0 Six-Coupled 0-8-0 Eight-Coupled 0-10-0 Ten-Coupled 0-10-2 Union You'll read about 4-8-8-2s being the Southern Pacific big "Cab Forwards". Actually, they were 2-8-8-4s with enclosed cabs and were built just for the SP due to the number and length of tunnels the SP operated through. The reason they operated "cab forward" was that, with the length of tunnels in the heyday of steam, SP found that operating engines in the "standard" configuration (at the rear of the boiler) the engine crew often could not see nor breathe simply because the tunnels had been designed before adequate ventilation methods existed to rid the tunnels of smoke & fumes. Here's a general breakdown, by the 11 largest roads, of the Class Identification letters applied to the various types of locos in the Whyte Classification series. Railroad ------------------------------------ B C C C G M M N P S S Engine & N B & N P I Y R O P Type O W & O L C R U Q W --------------------------------------------------------- 0-4-0 4-coupled | C K A S 0-6-0 6-coupled | D 2 G C A SW I B B A S 0-8-0 8-coupled | L M F C C SW D U C A SE 2-6-0 Mogul | K H E D E F D M 2-8-0 Consol. | E Z D G F C C G H 3 C 2-10-0 Decapod | Y D I D 2-6-2 Prairie | R J K J PR 2-8-2 Mikado | Q J O K O MK L H L M MK 2-10-2 Santa Fe | S M B Q SF N S F 2-8-4 Berkshire | J K BK A B 2-10-4 Texas | M T J 4-4-0 American | 1 2 A B E H D B E 4-6-0 Ten-Wheeler | B 2 K F E TN 4 F G T 3 4-4-2 Atlantic | A D P A K A AB I E C A 4-6-2 Pacific | P 2 S F H P F K K P P 4-8-2 Mountain | T B J P MT L M TS MT 4-6-4 Hudson | V E S L F J 4-8-4 Northern | H O J S S S GS A class of locomotives might be only one of several types on a particular road, all having the same wheel arrangement. To distinguish one class from another, the railroad companies usually assigned a class letter for the wheel arrangement and a number following it for the particular design. For instance, on the Milwaukee Road the letter S was used for all 4-8-4 type locomotives and an S3 was the third lot of engines, being newer than the S1 and S2 classes. However, each road had its own code, so the class number of one type on one road was not likely to be the same on the next. Also, while the systems were usually orderly at the start, exceptions and duplications crept in as new types of wheel arrangement were invented. For instance, the Milwaukee Road used the letter "F" for both the Pacific, 4-6-2 and its successor, the Baltic, 4-6-4, which on other roads is called a Hudson. When important differences existed in a class, small letters were tacked onto the class code. For instance, during the years when some Pennsylvania locomotives lacked superheaters, the small "s" in a class number such as the K4s indicates a locomotive with the superheater. In later years the "s" was dropped. The individual locomotive numbers were also usually used to show class groups. On any larger railroad all the locomotives in a given 100 numbers, such as for 1600 to 1699, were ususally of the same class as well. The Santa Fe used this method exclusively to indicate class while at the other extreme Pennsylvania locomotives were more often numbered for regions where they worked regardless of class. It was customary to start with an even 100 in numbering a type of import- ant class. For instance, the engines from 6400 to 6429 might all be 4-6-4 types on a particular road. This is misleading to the statistician in one respect, for it is easy to overlook #6400 and misread the total as 29 instead of the correct total of 30 locomotives