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The MARC 7100 Returns! (NOV. 99 CSX Railfan Magazine)

MARC 7100


Add this F-unit to the list of first generation locomotive survivors, as this "blast from the past" takes her place back on the home rails where she grew up!

Story & Photos by Joey Gonciarz


A little history!
Click to enlarge! Photo by Frank Kleczinski  

The original version of this F7-A was built by General Motors (EMD) in 1951. The unit was outfitted with the standard 1500 hp., 16 cylinder 567B diesel engine and sold to the B&O Railroad to be used in service throughout the system. This original F7-A was numbered by the B&O as #293A. She served the same purpose as many first generation diesels did, everyday service on B&O's vast lines. Time took its toll on this locomotive as it did with each unit in the fleet. Renumbered in early 1957 as #4553, this unit served the remainder of its time on B&O \ Chessie System till it was sold to (M&K) The Morrison - Knudsen

company (Boise, Idaho) on May 5, 1975 to be rebuilt or used as parts. Over the next few years,the unit remained idle at Boise (M&K at the time). The unit was transformed into a APCU (All Purpose Control Unit) push-pull cab unit with the removal of its prime-mover and replacement of a 6 cylinder HEP (Head-End Power) Cummins Diesel engine in the prime-mover's original place in the center of the car body along with a weight package. The traction motors were removed and replaced with idler wheel sets. For electrical coach power, a generator with all electrical fittings was coupled to the HEP to supply the standard 480 volts needed for coach lighting and air conditioning. Most accessories including the control stand, toilet, sand boxes and lights were left intact. Some body repairs were made to the metal skin as were welds of bad door panels and latches. The unit was then painted into a new version of the

Maryland Department of Transportation's (MDOT) orange & silver paint scheme, numbered MARC #7100 and was outshopped by Boise just prior to being delivered to the Maryland Department of Transportation on April 10, 1981. The unit was delivered to Washington, D.C. were it served MDOT commuters as a cab car style unit. At the same time this unit was rebuilt, 4 other F7-A units were also rebuilt. The other 4 units were essentially the same except that they were outfitted with a rebuilt version of their original prime-movers. All 5 units served with MDOT into the 1990's., when MDOT became MARC (Maryland Area Rail Commuter). The 4 powered units were never repainted into the "new" MARC paint scheme (different, but, a similar version of MDOT's orange & silver) and were traded back to (M&K) Boise Locomotive for credit on an order of 5 rebuilt GP39-W's. The 7100 remained in active service as a back-up cab car until its deterioration and placement in storage in late 1998. In late 1998, the decision was made to rebuild the APCU 7100 again.

  Click to enlarge! Photo by Frank Kleczinski
Almost Home!

The basis for the rebuild is a mystery to many, as some question the need for such an expensive rebuild just of a cab car style unit. This time, the rebuild would have to be extensive due to the advances in technology and the ever increasing safety rules put forth by the FRA in regards to stringent safety standards emerging in modern passenger service. After more than 1 year at Boise Locomotive (not named M&K anymore), the "ALL NEW" 7100 was returned to us at Riverside Locomotive Shops in Baltimore, Md. MARC's fleet of diesel locomotives are maintained by CSX Transportation as part of a operating and maintenance contract. Some MARC trains are operated on AMTRAK's North East Corridor (NEC) by AMTRAK crews, but, only MARC's Electric locomotive units are NOT maintained by CSX. These locomotives are serviced, maintained and operated by AMTRAK and are only operated on AMTRAK's "electrified" North East Corridor (NEC).

Home at last!

The 7100 arrived in Baltimore in late August 1999. Id' have to say that this unit was completely rebuilt if you were to compare it to its original configuration. The rebuild took more than 11 months at a cost of over $900, 000 to which the State of Maryland footed the bill. Changes were made to almost every part of the unit. (I guess you can't really call it a locomotive anymore, rather- APCU)

Click this image to enlarge!   Click this image to enlarge!   Click this image to enlarge!

SYSTEMS - The 7100's systems are now as modern as any locomotive or piece of equipment on any railroad. To power coaches with electricity for air conditioning, lights and running systems the 7100 was outfitted with Cummins latest diesel 6 cylinder engine. Producing a constant 480 trainline volts is accomplished by the Cummins KTA19G4, rated at over 600 hp at the generator. The engine was placed at the rear of the car body as seen through the back door in photo to left. As all MARC trains, at some point, may use AMTRAK's NEC, the need for cab signals is a must. The 7100 is no different from a cab car or locomotive in this respect. The 7100 was fitted with PULSE electronics' newest cab signal system as well as a PULSE III event recorder. Cab signal receivers are mounted at both ends and run on a 100 MHZ receiver base signal. The cab signal display is mounted between the two front windows with a standard 2 sided display for engineer and conductor.

Click this image to enlarge!

Braking on push-pull cab cars is very important as this end is now in the lead of a train with a powered locomotive pushing. The 7100 now has replaced 40 inch standard idler wheels with the newest in technology, "self adjusting single head brakes". A new Q-TRON computer controlled wheel slip\slide system manages the braking effectiveness with individual censors on each wheel. Speed censor data is sent to the computer with regards to MPH of each wheel enabling it to make minor adjustment.

Amenities are installed for comfort as well as safety, these include: New MARC paint scheme, Recess mounted ditch and class lights (as seen in photo), Toilet mounted in the forward section of the car body, as opposed to where it was located in the nose. Galvanized aluminum sand boxes are at 4 corners. ( standard is, lead axle sand, by FRA standards). New EMD style control stand and cab controls.

To conclude, the 7100 has nothing in the way of technology to be desired. The reasoning behind the rebuild remains a mystery. How can one justify the cost of such a rebuild for a powerless locomotive. I guess the only thing we can be certain of is "It sure looks good coming down the track" Hip Hip Hurray for whoever signed the ok on this thing.

Story & Photos by Joey Gonciarz

Thanks to Stuart Ammons and Frank Kleczinski for all the help!

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