Diesel Rolling Stock Parts

Diesel Engines

This diesel engine is light and compact, and it offers excellent durability, maintainability, and economy. We supply this product as a rolling stock diesel engine to a wide range of customers, including JR (Japan Railways), private railways, and third sector companies.

Hydraulic Transmissions

These split the direct coupled step into multiple steps and use the maximum output of the engine even at medium speeds in an attempt to increase transmission efficiency and improve acceleration. You can select from different models suitable for different types of railway cars, from express to standard vehicles.

CSU (constant speed unit)

The hydraulic multiple-plate slip clutch and electronic control automatically adjust the pushing pressure of the clutch plate according to the speed of the engine in order to maintain a constant speed.
It automatically shifts up to the optimal gear based on changes in the engine rotation speed, improving transmission efficiency.

Starting Motors

This motor is used to start the engine.
An engine starts when the built-in gears of the motor engage the engine gears and transmit rotational force to the engine. It is also sometimes called a “starter” or “starter motor.”

Reduction Gear

This device changes the direction of the rotational force transmitted along the drive shaft from the engine/fluid transmission, and it also reduces the speed and transmits the rotational force to the wheels.
Reduction gears used to be integrated with a reversing and reduction gears. Recent transmissions, however, contain a built-in reversing mechanism, and so today’s reduction gears have a simpler structure made up mainly with gears.

Preheaters

Normally, when the engine does not warm up, it is impossible to increase the temperature of the coolant or the heat source for warming that flows through the frame. This system, however, uses a boiler to warm the coolant, allowing it to warm the railway car.
In addition to warming coolant in the engine and easily starting the engine during cold weather, it also works extremely well as an auxiliary heat source for a hydronic heater to conserve energy and provide comfortable heating.

Mufflers

Offering excellent durability, this muffler has been widely installed in diesel rolling stock and locomotives since JR (Japan Railways) was Japanese National Railways.

Fuel Tanks

We manufacture fuel tanks to support a range of diesel/internal-combustion engine trains and locomotives.

Water Tanks

These large water tanks for locomotives offer superior durability.

Auxiliary Device Drive System Parts

These systems are for transmitting engine drive force to auxiliary devices, such as radiators and alternators.

Drive Shafts and Auxiliary Device Drive Shafts (Najico product)

These devices transmit power to rotation shafts that are not in line with the drive. We provide products that are designed and manufactured in-house to meet your needs.

Cooler/Radiator/Oil Cooler (Najico product)

Mainly used for engine cooling/hydraulic oil cooling/compressed air cooling for diesel rolling stock. We supply various types of heat exchangers for rolling stock inside and outside Japan. In addition to radiator cores, we also design and manufacture cooling systems and supply cooling systems with fan control functionality for diesel-hybrid railway cars.

Rooftop Cooling System (Najico product)

As a compact, integrated cooling system, this product is used in power-supply cars for passenger cars and the like.