California's Railroad to the U.S. 1861 - 1996

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Model Train Help EBook

Southern Pacific TR-6

4 TR6A units delivered

4 TR6B units delivered

TR6A units 4600 4601 4602 4603
TR6B units 4700 4701 4702 4703

Re# 1965
TR6A units 1100 1101 1102 1103
TR6B units 1150 1151 1152 1153
1150 1151 1152 1153

TR6A #1100 TR6A #1100
TR6A #1102 TR6A #1102

SW8 and TR6B at Roseville, date unknown... 150k

In 1950 EMD rolled out their SW-8 , a 567B powered 800 hp switcher, they also demonstrated a 'cow and calf' set designated TR-6, based on the SW-8, the TR standing for 'transfer'. Most modelers would instantly recall the Athearn (SW7) 'cow and calf' combinations.

Late 1950 EMD demonstrated their TR-6 set, numbered 1600 and 1600B, on the SP's Mina and Fallon branches. Due to the success of these, SP purchased these demonstrators, (in April 1951), kept the attractive two-tone red paint, and simply overpainted the Electro-Motive name with Southern Pacific. They were renumbered from 1600 and 1600B, to 4600 for the cab equipped A unit (cow), and 4700 for the B unit (calf).

In late 1951, SP received 3 TR6 sets, numbered 4601 to 4603 (A units) and 4701 to 4703 (B units), these were assigned to the Northwestern Pacific for road and transfer service.

The TR-6 units were built with drawbar connections, this feature didn't last very long. By 1953, they had replaced the drawbars with regular couplers.

In 1965 they werer renumbered, the A units were renumbered from #4600-4603 to #1100-1103, and the B units from #4700-4703 to #1150-1153.

Later in their lives, (around 1972), all four of the TR-6B units were paired with dynamic brake equipped SW-8's , #1109, 1112, 1113, and 1114, and assigned to the Roseville hump. The two remaining TR-6A's #1100 and 1102, were assigned to Los Angeles as standard SW-8's.

Rich Sievers has contributed this additional info:

The cows were actually separated from their calves while they were still assigned to the NWP and SP's Schellville Branch, operating out of Suisun. While I don't have the exact date, by 1955 the cows had been swapped with four Pacific Lines SW8s to take advantage of the dynamic brake feature on those units. The cows received headlights from retired steam engines on the rear ends (having been built without that appliance) and were then assigned to the LA Division (where 4602, at least, saw service on the PE and was equipped with trolley poles).

Around 1961, the four SW8s and the four TR6 B-units were reassigned to hump service at Roseville, where they remained until replaced with by MP15AC/slug sets. The B-units stayed in Roseville pending a program to convert them into slugs. However, the program was cancelled and they were sold off in 1979-1980.

Around 1975, the two remaining TR6 A-units, #1100 and 1102, were transferred from the LA Division to the Western Division, and both saw service in immediate Bay Area. #1100 would eventually replace SW1 #1004 as the shop goat at Sacramento, then was sold to Sierra Pacific Industries for use by the Quincy Railroad on SP's former Susanville Branch.

ex-SP 4600/1100 is still (10/28/2001) at the Sierra Pacific Industries mill in Susanville, as the back-up unit for their regular locomotive. And now in 2005 is now part of the rental units at the Feather River Rail Society at Portola, Ca.

Prototype References:

  • SP Dieselization by Garmany - Chapter 9 Postwar Diesel Switchers.
  • Extra 2200 South, Issue 56, Apr/May/Jun. 1976 - SP Roster, Part III

Additional Information on this Page contributed by Bruce Conklin, Joe Strapac, Rich Sievers and Eric Person.

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