I have just joined a railroad with an operable Plymouth DDT-6 locomotive, with a Detroit Diesel 4-71 and Allison transmission. I am looking for any Plymouth DDT-6 parts or service manuals. We already have a 4-71 manual available. Any manuals, tech pubs, and parts sources would be appreciated, particularly the Allison transmission.

Looking at Utah Rails and Preserved Critters, Dinkys and Centercabs (below list borrowed from Preserved Critters), it seems like the following locomotives are still around.


Plymouth DDT (36" ga.) Felton, Ca. Roaring Camp & Big Trees / tourist (6086)
Plymouth DDT (cast frame) Laws, Ca. Laws RR Museum (6092)
Plymouth DDT (24" ga.) Nevada City, Ca. Northern Queen Inn / Nevada Traction Co. / tourist (6220)
Plymouth DDT (24" ga.) Hesston, In. LaPorte County Hist. Steam Soc. (6034)
Plymouth DDT (24" ga.) Hesston, In. LaPorte County Hist. Steam Soc. (6069) (burned)
Plymouth DDT (24" ga.) Hesston, In. LaPorte County Hist. Steam Soc. (6151)
Plymouth DDT (24" ga.) Alna Center, Me. Wiscasset, Waterville & Farmington Ry. Museum (6290)
Plymouth DDT (24" ga.) Biddeford, Me. Biddeford Station
Plymouth DDT (24" ga.) (2) Portland, Me. Maine Narrow Gauge Museum
Plymouth DDT (24" ga.) South Carver, Ma. Edaville RR / tourist "Cranberry Belt" # 11 (7320)
Plymouth DDT (24" ga.) South Carver, Ma. Edaville RR / tourist "Cranberry Belt" # 12 (5970)
Plymouth DDT (36" ga.) Laughlin, Nv. Ramada Inn / tourist (6007)
Plymouth DDT (n.g.) Ashland, Pa. Pioneer Tunnel Anthracite Mine & Museum
Plymouth DDT (24" ga.) Leesport, Pa. Reading Lines RR Museum
Plymouth DDT St. Mary's, Pa. Bucksgahuda & Western / tourist
Plymouth DDT Nashville, Tn. Tennessee Central Ry. Museum (5732)
Plymouth DDT Kallagur, Q., Australia Alma Park Zoo / displayed as "steam loco"
Plymouth DDT Otrabanda, Willemstad, Curacao Curacao Museum

In addition, Reading Technical and Historical Society in Hamburg PA is the current custodian of Carpenter Steel 319 (Possible original number is 12, I would welcome any corrections.)

Does anyone know if other preserved Plymouth DDTs located in the US?

http://www.sonic.net/~jayreed/preserved.html
https://utahrails.net/loconotes/plymout ... otives.php

Roots of Motive Power at Willits, CA has a DDT. See here for all the Plymouth records: https://americanindustrialmining.com/pl ... tive-works

Thanks John, appreciate the info. That website seems like a wealth of knowledge.

Hi Pete,

Not sure how helpful the resource below might be; it’s an army technical manual for the DDT.

https://www.chartertoconductor.com/wp-content/uploads/2019/06/ply-om.pdf

Best,
Steve

Hi Steve,

That's a good resource too, I found it after my original request. I have used the Army 25, 44 and 45 ton manuals for our organization, they are a combination operation manual and minor service manual.

The Plymouth manual seems to be written for operations. The engine listed is a 100 hp 3-cylinder GM 3080, instead of the 160hp Detroit 4-71 we have. I'm not sure if the torque converter and transmission are the same.

The Army manuals are useful but limited, because they are written for people who aren't railroaders. "Plymouth Locomotives for Dummies" would be the modern equivalent.