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APU Idle Reduction Heating System


  • Engine



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Hotstart’s diesel fueled APU Idle Reduction Heater keeps locomotive engines warm in cold weather instead of idling engines

The HOTSTART Auxiliary Power Unit (APU) heating system is a self-contained water/coolant and oil preheater for locomotive prime movers. Utilizing an efficient Tier 4 Final engine, the APU consumes only a fraction of the fuel an idling locomotive uses while providing heat via four heat exchange points and a built-in tank heater – a total of 19 kW of total heating power supplied to the locomotive, lube oil and optional operator cab heater. The APU also supplies 80 amps of battery charging via a heavy-duty alternator. Designed from the ground up to work seamlessly with a locomotive’s day-to-day operations, the APU includes an easy-to-use operator interface, automatic operation, and integration capability with AESS systems.

By providing heat to the engine and lubrication oil, the HOTSTART APU allows locomotives to shut down in any location at any time while retaining the ability to restart immediately – even in the coldest conditions. Eliminating unnecessary idling and maintaining optimal start up temperatures for both critical engine components and oil reduces fuel consumption, oil consumption, emissions, noise pollution, engine wear, and wet-stacking.

Rail freight locomotives are susceptible to damage or delays due to freezing temperatures, requiring them to idle to maintain engine heat or be housed in climate-controlled locations. The HOTSTART APU frees locomotives from these limitations, allowing them to park and start up in any location at any time – maximizing their availability, prolonging their service intervals and allowing them to accommodate strict transport schedules.

Heat loss through wet cooling systems (wet radiator) during heating system operation may reduce or impair the heating system’s ability to maintain optimal heat levels for engine operation or engine start.

Not intended for hazardous locations.

Heating Information

Primary Heating

  • Water
  • Coolant Mix

Primary Heat Power

  • Coolant to coolant heat exchanger

Secondary Heating

  • Lubrication Oil

Secondary Heat Power

  • Coolant to oil heat exchanger

Mount Types

  • Foot

Inlets / Outlets


  • 24 JIC


  • 1” NPT

Secondary Inlets / Secondary Outlets

Secondary Inlets

  • N/A

Secondary Outlets

  • N/A

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