Union Pacific's Ex Missouri Pacific GP50s

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This page was last updated on May 18, 2024.

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Overview

Total of 30 units, numbered as MP 3500-3529

Total of 30 MP units went to UP at merger

First complete class of former MP locomotives to be repainted to Union Pacific yellow and gray, with Missouri Pacific lettering, completed in June 1984 through February 1985 (MP 3501 was the first, completed on 15 June 1984, and MP 3505 was the last, completed on 21 February 1985).

UP 50 Series

Only 12 units (UP 50, 57, 60, 61, 64, 65, 66, 70, 71, 74, 76, 78) were renumbered to the interim UP 50-79 series during 1988; the other 28 units were renumbered direct from MP 3500 series to UP 960 series.

Of the 30 units to UP at merger, 12 units were renumbered to the UP 50-79 group in January through October 1988 (UP 57, ex MP 3507, was the first, completed on 7 January 1988, and UP 50, ex MP 3500, was the last, completed on 18 October 1988).

UP 960 Series

All 30 units were renumbered to the UP 960-989 group in January 1989 through May 1992 (UP 963, ex MP 3503, was the first, completed on 4 January 1989, and UP 981, ex UP 71, ex MP 3521, was the last, completed on 22 May 1992).

Built without dynamic braking; dynamic braking was added to UP 960-969 (10 units), by VMV Enterprises, Paducah, Kentucky, in October 1992 through August 1993.

  Road
Number		 Date Dynamic
Braking Added
  UP 960 19 Nov 1992
  UP 961 22 Oct 1992
  UP 962 5 Nov 1992
  UP 963 25 Feb 1993
  UP 964 30 Mar 1993
  UP 965 17 Dec 1992
  UP 966 26 May 1993
  UP 967 12 Jul 1993
  UP 968 1 May 1993
  UP 969 23 Aug 1993

During mid-1992 Union Pacific initiated a program to add dynamic braking to ten ex-MP GP50's, UP 960-969, with plans to have dynamic braking added to the remaining 20 units as funding became available.  Missouri Pacific originally purchased the GP50s to operate at the head of MP's fast freights between Chicago and Texas, where much of the terrain is mostly flat.  After the 1982 merger with UP, and as the new UP's motive power needs changed, the GP50s were assigned to UP's four-axle general freight pool.  UP soon found that the GP50s were limited as to the actual freight service which they could be used in due to the lack of dynamic braking, and reassigned the units to intermodal trains in the old MP and along the lower-grade lines of UP's former Eastern District.

The advantages of intermodal service (i.e., dedicated train blocks or entire trains made up of long flat cars with trailers, and the articulated double-stack container cars) actually worked against the usefulness of the GP50s in that service. The lack of dynamic braking could not overcome the diminished air braking capability of the fewer number of axles that make up intermodal trains; fewer axles for braking due to longer cars and fewer axles on the articulated double-stack cars.

In 1992 EMD was asked to design an add-on dynamic brake feature for these 3500 horsepower four-axle racehorses. The units selected to receive the braking feature were UP 960-969, chosen to keep dynamic brake-equipped GP50s consecutively numbered after the six GP40Xs (UP 954-959), which were originally built with the feature.  As designed, the new braking for the 10 ex-MP GP50s would be high capacity and would require the addition of braking resistor grids and a cooling fan to the roof of the locomotives, along with modifications to the units' electrical cabinets.

As a side note, locomotive rebuilders, specifically Morrison Knudsen (MK), solved the problem of where to get the grids and actual sheet metal dynamic braking hatch components by using the actual components from retired locomotives that were equipped with the feature.  MK's solution when they added dynamic braking to ex-MP SD40s for part of a 50-unit rebuild order for CSX during 1990 included using the dynamic braking hatch from retired ex-BN SD45s.

Possibly because of both cost considerations and lack of availability of retired units, EMD chose to fabricate the new dynamic braking hatches for the ex-MP GP50s. The actual fabrication work, along with the electrical modifications and installation of the braking feature was done for EMD by VMV Enterprises at their shop in Paducah, Kentucky.  The units were modified in one and two unit batches as VMV was able to complete the hatch fabrication.  The first to be completed was UP 961 in October 1992, with UP 962, 960, and 965 following soon after in November and December.  Four more units (UP 963, 964, 967, and 966) followed in February through May 1993, with the last two units being outshopped in July and August respectively. VMV was subject to several delays in the completion of the project due to a lack of availability of some of the electrical components from its suppliers.

Six units in the UP 960 series were rebuilt to 2000 horsepower MP20GP yard locomotives in 2006.

UP 5558 Series

Of the 30 units to UP at merger, 29 units remained to be renumbered to the UP 5558-5587 series (UP 967 was retired in 1998); a total of 16 units were renumbered to the 5558-5587 series, including UP 5568, renumbered during August 2000, after the December 1999 assignment of the 1658-1687 series because the UP 1658 was still occupied by a GP15-1.

UP 1658 Series

Of the 30 units to UP at merger, 18 were renumbered to the UP 1658 series (12 units remained in the UP 960 series.)

The builder data for MP 3513, as UP 1671 has been changed to reflect a photo of the unit's builder plate.

Seven units in the UP 1658 series were rebuilt to 2000 horsepower MP20GP yard locomotives in 2006.

UPY 2100 Series

Seven units in the UP 1658 series, and six in the UP 960 series were rebuilt in April to December 2006 as MP 20GP locomotives by Motive Power International using 2000-horsepower Caterpillar diesel engines; renumbered to UPY 2100 series numbers.

Six of the UPY 2100 series were retired in September and October 2019.

  Road
Number		 Previous
Number		 Previous
Model		 Date Core Unit
Retired By UP		 Date
Completed		 Date
Delivered
  UPY 2100 UP 974 GP50 30 Nov 2004 20 Apr 2006 15 May 2006
  UPY 2101 UP 978 GP50 28 Jun 2005 12 May 2006 15 May 2006
  UPY 2102 UP 987 GP50 30 Dec 2004 5 Jun 2006 6 Jun 2006
  UPY 2103 UP 1684 GP50 7 Jun 2006 7 Jun 2006 7 Jun 2006
  UPY 2104 UP 1686 GP50 27 May 2005 13 Jun 2006 28 Jun 2006
  UPY 2105 UP 1660 GP50 30 Jun 2006 30 Jun 2006 10 Oct 2006
  UPY 2106 UP 1658 GP50 27 May 2005 7 Jul 2006 25 Jul 2006
  UPY 2107 UP 964 GP50 30 Sep 2004 25 Aug 2006 10 Oct 2006
  UPY 2108 UP 1659 GP50 20 Dec 2006 25 Aug 2006 19 Dec 2006
  UPY 2109 UP 969 GP50 19 Dec 2006 25 Sep 2006 19 Dec 2006
  UPY 2110 UP 965 GP50 19 Dec 2006 29 Sep 2006 19 Dec 2006
  UPY 2111 UP 1666 GP50 8 Jun 2007 27 Oct 2006 19 Dec 2006
  UPY 2112 UP 1664 GP50 20 Dec 2006 22 Dec 2006 28 Nov 2006

Roster Listing

EMD GP50 -- 30 units
3500 horsepower; B-B trucks; 268,000 pounds operating weight

Former Missouri Pacific GP50s. Total of 30 MP units went to UP at merger.

MP
Number		 Builder
Date		 Builder
Number		 Date To
MP Yellow		 UP 50 Series
Number		 Date To
UP 50 series		 UP 960
Series Number		 Date To
UP 960 Series		 UP 5558
Series Number		 Date To
UP 5558 Series		 UP 1658
Series Number		 Date To
UP 1658 Series		 Date
Retired		 UPY 2100
Series Number		 Notes
MP 3500 Nov 1980 797322-1 19 Dec 1984 UP 50 18 Oct 1988 UP 960 24 Oct 1991 UP 5558 12 Mar 1997 UP 1658 26 Apr 2004 27 May 2005 UPY 2106  
MP 3501 Nov 1980 797322-2 15 Jun 1984     UP 961 21 Feb 1989 UP 5559 4 Dec 1997 UP 1659 29 Jun 2004 20 Dec 2006 UPY 2108  
MP 3502 Nov 1980 797322-3 4 Sep 1984     UP 962 25 Apr 1989 UP 5560 6 Feb 1997 UP 1660 22 Jun 2004 30 Jun 2006 UPY 2105  
MP 3503 Nov 1980 797322-4 12 Sep 1984     UP 963 4 Jan 1989         (26 Nov 2003)   1
MP 3504 Nov 1980 797322-5 12 Sep 1984     UP 964 17 Jan 1992         30 Sep 2004 UPY 2107  
MP 3505 Nov 1980 797322-6 21 Feb 1985     UP 965 24 Oct 1989         19 Dec 2006 UPY 2110  
MP 3506 Nov 1980 797322-7 20 Sep 1984     UP 966 15 Dec 1989 UP 5564 9 Feb 1998 UP 1664 23 Aug 2002 20 Dec 2006 UPY 2112  
MP 3507 Nov 1980 797322-8 30 Dec 1984 UP 57 7 Jan 1988 UP 967 8 Feb 1990         31 Jul 1998   2
MP 3508 Nov 1980 797322-9 30 Dec 1984     UP 968 4 Jan 1990 UP 5566 2 Oct 1998 UP 1666 13 May 2004 8 Jun 2007 UPY 2111  
MP 3509 Dec 1980 797322-10 26 Sep 1984     UP 969 26 Feb 1990         19 Dec 2006 UPY 2109  
MP 3510 Jan 1981 807023-1 14 Dec 1984 UP 60 24 Jun 1988 UP 970 23 Aug 1989 UP 5568 4 Aug 2000 UP 1668 12 Apr 2004 11 Jun 2008    
MP 3511 Jan 1981 807023-2 19 Nov 1984 UP 61 16 Sep 1988 UP 971 14 May 1992         11 Jun 2008    
MP 3512 Jan 1981 807023-3 3 Dec 1984     UP 972 17 Feb 1989     UP 1674 9 Jun 2003 14 Sep 2007    
MP 3513 Jan 1981 807023-4 23 Oct 1984     UP 973 28 Sep 1990 UP 5571 14 Mar 1998 UP 1671 24 Apr 2004 11 Jun 2008    
MP 3514 Jan 1981 807023-5 24 Oct 1984 UP 64 6 Jul 1988 UP 974 13 Mar 1990         30 Nov 2004 UPY 2100  
MP 3515 Jan 1981 807023-6 19 Jul 1984 UP 65 4 Aug 1988 UP 975 13 Oct 1989 UP 5573 18 Dec 1997 UP 1673 4 Aug 2004 11 Jun 2008    
MP 3516 Jan 1981 807023-7 9 Nov 1984 UP 66 7 Oct 1988 UP 976 13 Sep 1991 UP 5574 4 May 1998 UP 1670 13 Jul 2004 11 Jun 2008    
MP 3517 Jan 1981 807023-8 4 Oct 1984     UP 977 31 Jul 1989         15 Jul 2002   3
MP 3518 Jan 1981 807023-9 21 Aug 1984     UP 978 15 Mar 1991         28 Jun 2005 UPY 2101  
MP 3519 Jan 1981 807023-10 6 Jan 1985     UP 979 8 Feb 1991 UP 5577 21 Sep 1998 UP 1675 19 Dec 2003 11 Jun 2008    
MP 3520 Jan 1981 807023-11 3 Aug 1984 UP 70 12 Aug 1988 UP 980 25 Jan 1990 UP 5578 15 Jan 1998     14 Apr 2004   4
MP 3521 Jan 1981 807023-12 21 Sep 1984 UP 71 15 Apr 1988 UP 981 22 May 1992 UP 5579 18 Mar 1997 UP 1679 11 Dec 2001 30 Sep 2004    
MP 3522 Jan 1981 807023-13 2 Aug 1984     UP 982 7 Feb 1991         11 Jun 2008    
MP 3523 Jan 1981 807023-14 5 Nov 1984     UP 983 13 Jun 1989 UP 5581 30 Dec 1998 UP 1681 7 May 2004 11 Jun 2008    
MP 3524 Jan 1981 807023-15 30 Oct 1984 UP 74 10 Oct 1988 UP 984 14 Oct 1991 UP 5582 23 Sep 1999 UP 1682 4 May 2004 11 Jun 2008    
MP 3525 Jan 1981 807023-16 14 Sep 1984     UP 985 12 Dec 1991 UP 5583 13 May 1997 UP 1683 16 Jul 2004 11 Jun 2008    
MP 3526 Jan 1981 807058-1 9 Dec 1984 UP 76 5 Sep 1988 UP 986 15 Jun 1990 UP 5584 28 Apr 1997 UP 1684 18 Feb 2002 7 Jun 2006 UPY 2103  
MP 3527 Jan 1981 807058-2 28 Aug 1984     UP 987 27 Feb 1989         30 Dec 2004 UPY 2102  
MP 3528 Jan 1981 807058-3 28 Nov 1984 UP 78 8 Sep 1988 UP 988 9 Jan 1990     UP 1686 8 Oct 2003 27 May 2005 UPY 2104  
MP 3529 Jan 1981 807058-4 14 Nov 1984     UP 989 3 Dec 1991 UP 5587 30 Aug 1999 UP 1687 30 Dec 2003 11 Jun 2008    

Notes:

  1. MP 3503, as UP 963 (assigned UP 5561, not renumbered) was converted to S6-1B road slug, completed as UPY 940 on 26 November 2003.
  2. MP 3507, as UP 967 was wrecked on 8 July 1998 at Redlands, California; sold for scrap to Pacific Rail Dismantlers.
  3. MP 3517, as UP 977 was converted to S6-1B road slug UPY 939, completed on 1 July 2003.
  4. MP 3520, as UP 5578 was wrecked on 10 February 2004 at Guyman, Oklahoma; still on property at time of planned arrival of new GE C44CCTE units, and was renumbered to temporary number WP 5578 on 24 June 2004 to avoid conflict (new GE number 5578 was delivered in August 2004).

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