Union Pacific F-unit Body features

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This page was last updated on January 30, 2014.

F-unit Carbody Styles

(from an original dated November 5, 1989)

For the purposes of this article the variations in the carbody styles of EMD's F3's and F7's are defined as follows:

Phase II F3 High radiator fans, wire screen radiator grilles, wire screen covered parallel dynamic braking vents, and wire screen between the portholes. Union Pacific had 35 units (15 A-units and 20 B-units), all built in 1947. Union Pacific did not own any of the earlier EMD FT, F2, and Phase I F3 models.

Phase III F3 Low radiator fans, wire screen radiator grilles, and wire screen covered parallel dynamic braking vents. The variations within this carbody style are in the area between the portholes, below the radiator grilles, where openings were located for some of the engine intake air filters. The early version had wire screen between the portholes. The middle version had just square openings for the carbody filters, and the late version had horizontal louvers. Union Pacific had F3's built during the eras that the early and middle versions were being used. However photographic research has shown that there is now some confusion about the time frames for each of these features. And to confuse things even further, the photo of 1450 shows that it had horizontal louvers between the portholes - a feature that supposedly no Union Pacific F3 should have. All of this can best be explained by the fact that all of the carbody panels were interchangeable, with all of the parts being available from EMD. Some changing may have taken place as the units were shopped at various times during their time on the railroad.

Phase IV F3 Low radiator fans, horizontal finned radiator grilles, horizontal louvers between the portholes, and wire screen covered parallel dynamic braking vents. Union Pacific had 52 units (22 A-units and 30 B-units) built between September 1948 and January 1949.

Phase I F7 Low radiator fans, horizontal finned radiator grilles, horizontal louvers between the portholes, and 36 inch dynamic braking fan.

Phase II F7 Low radiator fans, vertical slit radiator grilles, and 36 inch dynamic braking fan. The variation within this carbody style comes from the louvers between the portholes. The early version has the horizontal style and the late version has the vertical style. Research shows that while all of Union Pacific's F7's should be Phase I F7's, photographs show that all of them are in fact Phase II F7's; they have the vertical slit radiator grilles. Also the rebuilt wrecked units and the former demonstrators aren't what they should be. All records show that the UP 1464 should be an F7, but the photograph of the unit shows that it was a Phase IV F3. The same has been found of the 1482. This unit should be a Phase II F7, but its photo shows it with Phase IV F3 features.

UP's F3 and F7 Carbody Differences

(from an original dated September 29, 1992)

FTs

- in production between October 1939 and November 1945
- none on UP

F2s

- in production July 1946 to November 1946
- none on UP

F3s (Phase I)

- in production November 1946 to May 1947
- none on UP

F3s (Phase II)

(RMC Phase IIa)

- in production May 1947 to April 1948
- High radiator fans
- Wire screen radiator grilles
- Wire screen covering parallel dynamic braking vents
- Wire screen between portholes

- UP had 35 units (15 As and 20 Bs)
- delivered in May, September, and October 1947

- 1400A-1409A (1400-1409) 10 units, built 5,10/47
- 1442B-1451B (1400B,C-1408B,C) 10 units, built 5,10/47
- 964A-968A (900-904) (1451-1455) 5 units, built 9,10/47
- 969B-978B (900B,C-904B,C) (1451B,C-1455B,C) 10 units, built 9/47

Photo research:
- 964A, 900, 901
- 1406A, 1401, 1404

F3s (Phase IIIa)

(RMC Phase IIb)

- in production December 1947 to April 1948
- Low radiator fans
- Wire screen radiator grilles
- Wire screen covering parallel dynamic braking vents
- Wire screen between portholes

- UP had 64 units, 38 As and 26 Bs
- delivered between January and June 1948

- 905-910 (1456-1461) 6 units, built 5,6/48
- 905B,C-909B,C (1456B,C-1458B,C) 6 units, built 5,6/48
- 1410-1441 (1410A-1441A) 32 units, built 1,2,3/48
- 1410B,C-1428B,C (1452B-1471B) 20 units, built 1,2,3/48

Photo research:
- 905, 906
- 1410, 1413, 1420, 1425, 1430, 1432, 1438, 1439, 1444, 1445, 1446, 1447
- 1445 had high fans in 1959, 1447 had high fans in 1954

F3s (Phase IIIb)

(RMC Phase III)

- in production April to July 1948
- Low radiator fans
- Wire screen radiator grilles
- Wire screen covering parallel dynamic braking vents
- Wire screen over the square filter openings

- UP had 28 units (14 As and 14 Bs)
- delivered between April and July 1948

- 1442-1455 14 units, built 4,5,7/48
- 1442B,C-1454B,C (even) 14 units, built 4,5,7/48

Photo research:
- 1417, 1434

F3s (Phase IIIc)

- in production July to August 1948
- Low radiator fans
- Wire screen radiator grilles
- Wire screen covering parallel dynamic braking vents
- Horizontal louvers between the portholes

- none on UP

Photo research:
- 1450 in 1956

F3s (Phase IV)

- in production September 1948 to February 1949, end of F3 production
- Low radiator fans
- Horizontal finned radiator grilles
- Horizontal louvers between the portholes
- Wire screen covering parallel dynamic braking vents

- UP had 52 units (22 As and 30 Bs)
- delivered between September 1948 and January 1949

- 1456-1463 8 units, built 9/48
- 1430B,C-1440B,C (even) 12 units, built 9,12/48, 1/49
- 1456B,C,1458B,C 4 units, built 9/48
- 1550-1563 14 units, built 10,11,12/48, 1/49
- 1550B,C-1562B,C 14 units, built 10,11,12/48, 1/49

Photo research:
- 1464, 1482
- 1560, 1561

F7s (Phase I)

- in production November 1948 to November 1951
- Low radiator fans
- Horizontal finned radiator grilles
- Horizontal louvers between the portholes
- 36" dynamic braking fan

- UP had 45 units (15 As and 30Bs)

- 1466-1470 5 units, built 3/51
- 1466B,C-1474B,C (even) 10 units, built 3/51
- 1471-1480 10 units, built 10/51
- 1476B,C-1494B,C 20 units, built 10/51

- 1483, new 7/50, to UP 1/53

F7s (Phase IIa)

- in production November 1951 to February 1952
- Low radiator fans
- Vertical slit radiator grilles
- Horizontal louvers between portholes
- 36" dynamic braking fan

Photo research:
- 1467, 1468, 1471, 1478

F7s (Phase IIb)

- in production February 1952 to December 1953
- Low radiator fans
- Vertical slit radiator grilles
- Vertical louvers between portholes
- 36" dynamic braking fan until about August 1952, then 48" fan

- UP had 4 units (2 FP7s and 2 Bs)

- 911, 912 (1498, 1499) 2 units, built 4/52
- 910B,C (1498B,C) 2 units, built 4/52

- 1481, 1482 new 8/52, to UP 12/52
- 1482 has Phase IV F3 appearance, which supposedly ended in 11/48

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