The DE 18000 locomotive is a diesel-powered, electric-drive shunting and light-duty locomotive with a Bo’Bo’ axle configuration. These units were imported in limited numbers (5 units) in 1970 by the Turkish State Railways (TCDD) for use on tracks with low axle load requirements. Structurally, they incorporate the basic features of diesel-electric propulsion systems.

Diesel-Electric Propulsion System

As stated in the MEGEP “Railway Vehicles” module, in diesel-electric locomotives, the mechanical energy generated by the diesel engine is converted into electrical energy through an alternator or generator. This electricity is then used by traction motors to drive the wheels. This system provides the following advantages:

• High tractive effort and torque
• Efficient operation even at low speeds
• Simple power transmission
• Compatibility with Multiple Unit (MU) connections

The DE 18000 locomotives incorporate all fundamental principles of this system. The Pielstick diesel engine and generator system in the vehicle supply electricity to the traction motors, enabling the independent drive of all four axles in the Bo’Bo’ configuration.

Bo’Bo’ Axle Configuration and Light-Duty Characteristics

The Bo’Bo’ axle layout consists of two bogies, each with two axles, and each axle is powered by a separate traction motor. This configuration offers the following advantages in light-duty and shunting locomotives like the DE 18000:

• Lower overall weight
• Reduced load on the rails (axle load)
• High maneuverability on tight curves
• Rapid acceleration and braking

These features directly match the characteristics described in the MEGEP module for diesel-electric shunting locomotives.

_{DE 18000 Locomotive (AI-Generated Image)}

Role Within the Train Set

According to MEGEP’s “Formation and Control of Train Sets” module, traction units are evaluated based on the following technical criteria:

• Braking Compatibility: The locomotive’s braking system must be compatible with the coupled wagons. In this context, the DE 18000 is equipped to integrate with both the locomotive’s braking system and the trainset’s brake line.
• Load Distribution: Light locomotives can be positioned at the front or rear of partially loaded trainsets for balancing purposes.
• Traction Capacity: Thanks to the constant torque structure provided by the diesel-electric system, locomotives like the DE 18000 can operate efficiently on short-distance and low-load routes.

Training and System Compatibility

DE 18000-type locomotives systematically include the following subsystems as described in the MEGEP modules:

• Traction Control System: Integrated with diesel engine RPM and load control systems
• Electrical Distribution Unit: Includes main generator, auxiliary generator, battery group, and motor control relays
• Braking System: Pneumatic braking systems with electric control panels
• Safety Equipment: Thermal protection, overcurrent circuit breaker, motor speed control system

All these components are systematically present in the DE 18000 model and are detailed in vocational training modules.

Considering the technical definitions and system descriptions in the MEGEP modules, the DE 18000 series locomotives are safe, balanced, and technically adequate solutions for low-demand routes. Although these locomotives are no longer in active service today, they are regarded as significant examples of Türkiye’s experience with diesel-electric light-duty rail vehicles during the modernization of the railway system.

_{Start-Up of a DE 18000 Locomotive Belonging to TCDD (Umut Baki Gezgiç)}