Editing 2-10-10-2

{{Short description|Mallet locomotive wheel arrangement}}
Under the [[Whyte notation]] for the classification of [[steam locomotive]] [[wheel arrangement]]s, a '''2-10-10-2''' is a locomotive with two [[leading wheel]]s, two sets of ten [[driving wheel]]s, and a pair of [[trailing wheel]]s.

Other equivalent classifications are:
:[[UIC classification]]: '''1EE1''' (also known as German classification and [[Swiss classification]])
:[[Italian and French classification]]: '''150+051'''
:[[Turkish classification]]: '''56+56'''
:[[Swiss classification]]: '''5/6+5/6'''

The equivalent [[UIC classification]] is refined to '''(1′E)E1′''' for Mallet locomotives. All 2-10-10-2 locomotives have been [[articulated locomotive]]s of the [[Mallet locomotive|Mallet]] type.

This wheel arrangement was rare. Only two classes of 2-10-10-2 locomotives have been built: the [[Atchison, Topeka and Santa Fe Railway]]'s '''3000 class''', and the [[Virginian Railway]]'s '''class AE'''. The 3000 class performed poorly, so the railroad returned them to their original 2-10-2 configuration after no more than seven years of service. The class AE locomotives were much more successful, providing between 25 and 31 years of service; some were scrapped between 1943 and 1945, and the rest were scrapped between 1947 and 1949. None of either class were preserved.

== ATSF 3000 class ==
{{No sources section|date=July 2024|find=ATSF 3000 class}}
{{Infobox locomotive
| name = ATSF 3000 class
| image = Detroit Publishing - New Mallet articulated compound engine on the Santa Fe (sky cropped).jpg
| alt = 
| caption = ATSF 3000 class 2-10-10-2. The forward section of the boiler is a primitive [[superheater]] and [[feedwater heater]]
| powertype = Steam
| designer = 
| builder = [[Baldwin Locomotive Works]]
| ordernumber = 
| serialnumber = 
| buildmodel = 
| builddate = 1911-1912
| totalproduction = 
| rebuilder = [[ATSF]]
| rebuilddate = 1915-1918 (as 2-10-2’s)
| numberrebuilt = 10
| website = 
| whytetype = 2-10-10-2
| uicclass = 
| driver = <!-- e.g. 1st, 2nd  or 3rd coupled axle -->
| gauge = {{track gauge|ussg}}
| leadingdiameter = 
| driverdiameter = {{convert|57|in|m|3|abbr=on}}
| trailingdiameter = 
| tenderdiameter = <!-- tender wheel diameter -->
| minimumcurve = 
| wheelbase = {{convert|108|ft|10|in|m|abbr=on}}
| engine total = 
| leading = 
| drivers = <!-- USA terminology -->
| coupled = <!-- British terminology -->
| trailing = 
| tender total = 
| tendertruck = <!-- USA terminology -->
| tenderbogie = <!-- British terminology -->
| pivotcentres = <!-- Garratts, diesels and electrics -->
| wheelspacing = <!-- coupled wheels with asymmetrical wheel spacing -->
| length = {{convert|122|ft|m|2|abbr=on}}
| over couplers = 
| over bufferbeams = 
| width = 
| height = 
| frametype = 
| axleload = 
| leadingbogie/pony = <!-- load on leading bogie or pony wheel -->
| coupled all = <!-- when the load on all coupled wheels are the same -->
| coupled 1 = <!-- load on 1st coupled wheel -->
| coupled 2 = <!-- load on 2nd coupled wheel -->
| coupled 3 = <!-- etc. -->
| coupled 4 = 
| coupled 5 = 
| coupled 6 = 
| coupled 7 = 
| coupled 8 = 
| trail bogie/pony = <!-- load on trailing bogie or pony wheel -->
| tenderbogieload = <!-- load per tender bogie, use "Truck 1:<br />Bogie 2:" if different -->
| tenderaxle = <!-- use "Axle 1:", etc with "<br />" for line breaks -->
| weightondrivers = 
| locoweight = {{convert|616,000|lb|kg t|sigfig=4|abbr=on}}
| tenderweight = {{convert|266,400|lb|kg t|abbr=on}}
| locotenderweight = 882,400 lb (400,180 kg; 400.18 t)
| tendertype = 
| fueltype = 
| fuelcap = 
| watercap = 
| tendercap = 
| sandcap = 
| fireboxtype = <!-- Round-top, Belpaire, combustion chamber, etc. -->
| firearea = 
| boiler = <!-- Watson Standard no. x, etc -->
| boilertype = <!-- Domeless, etc -->
| pitch = <!-- height of boiler centreline above the railhead -->
| diameterinside = 
| lengthinside = <!-- distance between tube plates -->
| smalltubediameter = <!-- number of boiler tubes and their outside diameter -->
| largetubediameter = <!-- number of larger tubes (flues), if any, and their outside diameter -->
| boilerpressure = {{convert|225|psi|MPa|abbr=on}}
| safetyvalvetype = <!-- Salter spring balance, Ramsbottom, Pop, etc. -->
| feedwaterheater = 
| totalsurface = 
| tubearea = 
| archarea = 
| fluearea = 
| tubesandflues = 
| fireboxarea = 
| superheatertype = 
| superheaterarea = 
| cylindercount = Four, compound (LP front, HP rear)
| hpcylindersize = {{convert|28|x|32|in|mm|0|abbr=on}}
| lpcylindersize = {{convert|38|x|32|in|mm|0|abbr=on}}
| valvegear = 
| valvetype = 
| valvetravel = 
| valvelap = 
| valvelead = 
| transmission = 
| trainheating = 
| locobrakes = 
| locobrakeforce = 
| trainbrakes = 
| safety = 
| coupling = 
| maxspeed = 
| poweroutput = 
| tractiveeffort = {{convert|111600|lbf|kN|abbr=on}}
| factorofadhesion = 
| operator = [[Atchison, Topeka and Santa Fe Railway]]
| operatorclass = 
| powerclass = 
| numinclass = 
| fleetnumbers = 3000–3009
| officialname = 
| nicknames = 
| axleloadclass = 
| locale = 
| deliverydate = 
| firstrundate = 
| lastrundate = 
| withdrawndate = 1945-1953
| restoredate = 
| scrapdate = 1947-1953
| currentowner = 
| disposition = All scrapped
| notes = 
}}

In 1911 and 1912,  the [[Atchison, Topeka and Santa Fe Railway]] modified ten [[2-10-2]] [[Baldwin Locomotive Works|Baldwin]]-built locomotives into a new 2-10-10-2 configuration dubbed the 3000 class. They were the largest locomotives in the world from their introduction until 1914. They performed well in helper service, but could only go {{cvt|10 to 15|mph}} before losing steam. The ATSF reverted them to their 2-10-2 configurations between 1915 and 1918.

{{clear}}

== Virginian Railway class AE ==
{{One source|section|date=August 2024|find=Virginian Railway class AE}}
{{Infobox locomotive
| name = Virginian Class AE
| powertype = Steam
| builder = [[American Locomotive Company]]
| ordernumber = 1227
| image = Virginian Railway AE.jpg
| caption = Virginian Class AE
| hatnote = Reference:<ref name=bruce/>
| builddate = 1918
| totalproduction = 10
| whytetype = 2-10-10-2
| gauge = {{Track gauge|ussg}}
| driverdiameter = {{convert|56|in|mm|0|abbr=on}}
| wheelbase = {{convert|64.25|ft|m|abbr=on}}
| weightondrivers = {{convert|617000|lb|kg t|0|abbr=on}}
| locoweight = {{convert|684000|lb|kg t|0|abbr=on}}
| tenderweight = {{convert|214300|lb|kg t|0|abbr=on}}
| locotenderweight = {{convert|898300|lb|kg t|0|abbr=on}}
| fueltype = [[Coal]]
| watercap = {{convert|13000|USgal|impgal L|0|abbr=on}}
| tendercap = {{convert|12|ST|LT t|1}}
| boiler = {{convert|118.5|in|mm|0|abbr=on}}
| boilerpressure = {{convert|215|psi|MPa|0|abbr=on}}
| firearea = {{convert|108.7|sqft|m2|0|abbr=on}}
| totalsurface = {{convert|8528|sqft|m2|0|abbr=on}}
| tubearea = {{convert|5580|sqft|m2|0|abbr=on}}
| archarea = {{convert|438|sqft|m2|0|abbr=on}}
| fluearea = {{convert|2510|sqft|m2|0|abbr=on}}
| superheaterarea = {{convert|2120|sqft|m2|0|abbr=on}}
| cylindercount = Four, compound (LP front, HP rear)
| lpcylindersize = {{convert|48|x|32|in|mm|0|abbr=on}}
| valvegear = [[Walschaerts valve gear|Walschaerts]]
| hpcylindersize = {{convert|30|x|32|in|mm|0|abbr=on}}
| tractiveeffort = Compound: {{convert|147200|lbf|kN|0|abbr=on}}<br />Simple: {{convert|176600|lbf|kN|0|abbr=on}}
| factorofadhesion = 4.19
| locobrakes = [[Railway air brake|Air]]
| trainbrakes = Air
| numinclass = 10
| fleetnumbers = 800-809
| operator = Virginian
| disposition = All scrapped from 1943-1953
| width = {{convert|12.0|ft|m|3|abbr=on}}
| height = {{convert|16.625|ft|m|3|abbr=on}}
}}

These ten locomotives were built in 1918 by [[American Locomotive Company|ALCO]] for the [[Virginian Railway]]. With a width of {{convert|12|ft|mm|0}}, they were delivered without their cabs and front low-pressure cylinders and were assembled after delivery. The {{convert|48|in|mm|0|adj=on}} low-pressure cylinders (on {{convert|90|in|mm|0|adj=on|disp=or}} centers) were the largest on any U.S. locomotive; these had to be inclined a few degrees to provide clearance.<ref name="bruce" /> The boiler was also the widest of any locomotive; Railway Mechanical Engineer says "the outside diameter of the largest course is {{convert|112+7/8|in|mm|0}}." but the drawing shows {{convert|118+1/2|in|mm|0}} diameter at the rear tube sheet. Their accompanying fuel [[tender (rail)|tenders]] were shorter than usual so the locomotive would fit on the Virginian's [[turntable (railroad)|turntables]].

This class were compound [[Mallet locomotive]]s. The rear, high-pressure cylinders exhausted their steam into the huge front cylinders.  They could also be operated in simple mode for starting; reduced-pressure steam could be sent straight from the boiler to the front cylinders at low speed, for maximum tractive effort.

The calculated tractive effort was {{convert|147,200|lb|kg|abbr=on}} in compound, or {{convert|176,600|lb|kg|abbr=on}} in simple for the Virginian locomotives.<ref>{{cite book |last1=Lewis |first1=Lloyd D. |title=Virginian Railway Locomotives |date=1993 |publisher=Walsworth Publishing Co. |location=[[Marceline, Missouri]] |isbn=1-883089-05-0 |page=32 |edition=1}}</ref>

The class remained in service until the 1940s. No examples have been preserved.<ref name="bruce" />

==References==
{{reflist
|refs=

<ref name="bruce">{{cite book|last=Bruce|first=Alfred|title=The Steam Locomotive in America: Its Development in the Twentieth Century|publisher=W.W. Norton|location=New York|pages=321, photo 85}}</ref>

}}

{{commons|position=left}}

{{Whyte types}}

[[Category:Whyte notation|1010,2-10-10-2]]
[[Category:Atchison, Topeka and Santa Fe Railway locomotives|3000]]
[[Category:Virginian Railway locomotives|AE]]
[[Category:Steam locomotives of the United States]]
[[Category:Railway locomotives introduced in 1911]]