Tuesday, May 31, 2011

ALP-45DP: Two locomotives in one

Written by  William C. Vantuono, Editor-in-Chief
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ALP-45DP: Two locomotives in one William C. Vantuono

There are two constants about regional rail that most agencies will agree upon: 1) Customers prefer a one-seat ride. 2) Electrification has many benefits, but it’s very expensive. This locomotive, Bombardier Transportation’s ALP-45DP dual-power, which NJ Transit and AMT (Montreal) are acquiring in a joint procurement, addresses both these issues.

In non-electrified territory, twin EPA Tier 3-compliant, 12-cylinder Caterpillar 3512HD (High Displacement) diesels running at up to 2,100 rpm provide a combined 4,200 hp, a starting tractive effort of 71,000 pounds, and a top speed of 100 mph. In electric mode, drawing power from a.c. catenary, a transformer virtually identical to that in the ALP-46A provides 5,360 hp of traction power and a top speed of 125 mph.

Changing between diesel and electric modes is simple and does not interrupt head-end power. To change from diesel to electric, the operator engages the Pantograph Up switch. To change from electric to diesel, the operator engages the Fault Reset button. In either case, changeover takes approximately 100 seconds, and there is automated voice acknowledgement. No electrical modifications were required for NJT’s existing cab control cars or trailer coaches, so, in effect, the ALP-45DP is a “plug and play” locomotive.

Designed and engineered by Bombardier in cooperation with STV, Inc. and the two transit agencies, the ALP-45DP is based upon the four-axle ALP-46A electric, which itself is based upon Bombardier’s European TRAXX locomotive. It shares many components and systems with its electric cousin. Among these are the fully suspended drive system, Bombardier MITRAC® TC3360DPV01 IGBT traction converter, and cab layout. The locomotive weighs in at 284,000 pounds—8,000 pounds less than the threshold for operating at speeds greater than 79 mph on the Northeast Corridor—fully fueled with 1,800 gallons of diesel fuel in four compartmentalized 450-gallon tanks, two for each engine. It is 14 feet, 5-1/4 inches high; 71 feet, 6-1/4 inches long; and 9 feet, 8-1/8 inches wide, with a 71,000-pound axle load. Truck axle base is 9 feet, 2-1/4 inches. The carbody is within Amtrak’s A-05-1355 clearance diagram. Structurally, it meets 49 CFR Part 238 (Tier 1 Passenger Equipment Crashworthiness), 49 CFR Part 229 (Locomotive Crashworthiness), AAR S-580, and APTA SS-C&S-034-99 requirements. The fuel tanks, which are integral with the monocoque carbody, meet 49 CFR Part 223 and AAR S-5506 requirements.

Due to length and weight requirements, the ALP-45DP is a single-cab, single-pantograph (Transtech) design. It’s equipped with a Hotstart AESS system, Wabtec brakes, and a PHW-supplied ACSESII automatic train protection/9-aspect cab signal system (only on the NJT version). Braking effort in regenerative electric mode is 34,000 pounds; dynamic braking power in diesel mode is 1,767 hp. It’s got a specially designed water/nitrogen fire suppression system. The ALP-45DP is on schedule to begin revenue service by year-end 2011. Bombardier says there is U.S. interest in this new breed of passenger locomotive among other transit agencies, both in and outside the NEC.

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