UP orderd their TR5's with gearing that permitted a maximum 55mph, which proved unnecessary in helper service. Being capable performers did not prevent them from being displaced in helper service by GP-7's and reassigned throughout the system where their speed, TE and reliabilty made them popular on locals and transfers from Albina to Odgen. In 1968 significent changes occured among the TR5's with the removal of dynamic brake equiptment and installation of 1400ga fuel tanks to several for hump yard service.
SP also rostered 2 A units and 2 B units of the TR6 model, based upon the SW8, assigned to Roseville they were ordered with low speed gearing, additional ballast and no mu capability.
Unlike those of the Union Pacific, SP eventually broke their sets up and all fell victim to the purge of low HP models that occured throughout seventies. UP TR5's went from cradle to grave as matched sets until retired in 1982.
Dave
mobilman44The switchers - be it cow or calf - were and are used for many jobs, with the biggest constraint being speed. Obviously they were geared for low speeds, although they have excellent "pulling power" for their size.
Indeed.. The roster of the Pittsburg and Sawmut was all SW9 switchers
Larry
Conductor.
Summerset Ry.
"Stay Alert, Don't get hurt Safety First!"
BRAKIE ericsp They changed the model to SW7 (I don't know if that was correct) shortly before coming out with a correct model of the SW1500. The first so called SW1500 was indeed a SW7.. Trains Inc made a brass TR6 cow/calf set with KMT drives.
ericsp They changed the model to SW7 (I don't know if that was correct) shortly before coming out with a correct model of the SW1500.
The first so called SW1500 was indeed a SW7.. Trains Inc made a brass TR6 cow/calf set with KMT drives.
Looks like I have phony SW1500's - but they're still quite nice :-)
The switchers - be it cow or calf - were and are used for many jobs, with the biggest constraint being speed. Obviously they were geared for low speeds, although they have excellent "pulling power" for their size.
And while it may not look right to some, those calfs (spell?) can be hooked up to most any loco to do their thing.
ENJOY !
Mobilman44
Living in southeast Texas, formerly modeling the "postwar" Santa Fe and Illinois Central
ericspThey changed the model to SW7 (I don't know if that was correct) shortly before coming out with a correct model of the SW1500.
Athearn originally called those locomotives SW1500s, but they were not models of SW1500s. They changed the model to SW7 (I don't know if that was correct) shortly before coming out with a correct model of the SW1500.
"No soup for you!" - Yev Kassem (from Seinfeld)
I'm envisioning a calf MU'ed with a FxB with a hostler's window. Almost scary. But it would work as a hump switcher.
Ed
The 'calf' doesn't have to be the same model as the 'cow.' All it needs is a compatable control system. For that matter, quite a few 'calves' were former full-cab units that were downgraded after later models with better (and better-equipped) cabs became available.
The next step down the ladder is the slug, which is simply a set of traction motors under a weight, with or without a cab. Slugs didn't have to be the same model, or even the same type of loco. IIRC, the NYC acquired some steeple-cab electrics and converted them to slugs for yard service, interurban-style trucks and all. As long as the traction motors are happy with the same voltage as those under the 'cow,' they're good.
Chuck (Modeling Central Japan in September, 1964 - with diesel-hydraulic locos and torque converter DMU)
In 1951, Union Pacific accepted delivery of eight TR5 A units 1870-1877 and eight TR5 B-units 1870B-1877B (contempories of the SW9) cow-calf units specifically for helper operations over Cajon Pass and the 2.2% grade of Cima Hill out of Kelso to the east where they replaced tempermental FM H20-44's that proved unreliable in sustained road service.
A significent mechanical and operating improvement was the application of dynamic brakes to the A units in 1953 to reduce premature brake shoe wear and overheated wheels. When not occupied with helper assignments, the TR's were assigned to the numerous locals common during that period that traversed the pass.
The EMD 'Cow & Calf' sets were originally built as drawbar connected sets. Later, some railroads 'seperated' the sets and used the Calfs as needed. I remember seeing a Cow/F7B/Calf working the Milwaukee hump yard south of St Paul in the 70's. I sort of doubt that they were used very often in 'road service' Usually the switchers were geared for less that 55 mph, and many time they could not make transition to full parallel - unless the owning line went to a lot of trouble/expense to upgrade them.
IIRC, the C&O did order Cow/Calf/Calf sets, and I have heard they were used on some mine run locals or transfers - It's you railroad....
Jim
Modeling BNSF and Milwaukee Road in SW Wisconsin
I've got a few Athearn Blue Box SW-1500 Calves - not not the Cow. Have railroads used the Calf as a "helper" for other engines - SD-9, GP-9, FP45, U28, etc.?