1. Introduction
Thank you for choosing the Piko 51606 Expert PKP ET21 Electric Locomotive. This H0 scale model is a detailed replica of the historically significant Polish freight train locomotive, representing a milestone in traction change in Poland. Piko Expert models are known for their precision and attention to detail, and the ET21 is no exception.
This manual provides essential information for the safe setup, operation, and maintenance of your model locomotive. Please read it thoroughly before use to ensure optimal performance and longevity of your product.

Figure 1: Full side view of the Piko 51606 Expert PKP ET21 Electric Locomotive. This image highlights the detailed bodywork, bogies, and roof equipment.
Key features of this model include finely engraved and highly detailed fan grilles, precisely cast open bogie frames, and filigree roof equipment. The model boasts an exceptional paint finish and accurate printing. It is powered by a five-pole PIKO motor with two flywheels, ensuring smooth operation. The locomotive is equipped with a PLUX22 interface for easy installation of a digital decoder or sound module.
2. Safety Information
Important Safety Warnings:
- This item is NOT a toy and is intended for modeling use by experienced hobbyists.
- Not suitable for children under 3 years of age due to small parts which may present a choking hazard.
- Always handle the model with care to avoid damage to delicate components.
- Ensure the power supply is disconnected before performing any maintenance or modifications.
- Operate the locomotive on a clean, dry track to prevent electrical shorts or damage.
3. Package Contents
Upon opening the package, please verify that all components are present and undamaged:
- 1x Piko 51606 Expert PKP ET21 Electric Locomotive
- 1x Instruction Manual (this document)
- Small parts bag (e.g., additional coupling parts, brake hoses, etc. - specific contents may vary)
If any parts are missing or damaged, please contact your retailer or Piko customer support immediately.
4. Setup
4.1 Preparing the Locomotive
Carefully remove the locomotive from its packaging. Inspect it for any visible damage from transport. Ensure all small, loose parts (if any are included separately) are securely attached or stored for later use.

Figure 2: Front view of the Piko 51606 ET21 locomotive, showing the detailed front section and pantographs.
4.2 Placing on Tracks
Gently place the locomotive on your H0 scale tracks. Ensure that all wheels are correctly seated on the rails. The locomotive is designed for a minimum radius of 358mm.
4.3 Power Connection (DC Operation)
This model is designed for Direct Current (DC) operation. Connect your DC power pack to the track according to the power pack's instructions. Ensure the voltage is appropriate for H0 scale models (typically 0-12V DC).
4.4 Digital Decoder Installation (Optional)
The locomotive features a NEM 658 PLUX22 interface for easy installation of a digital decoder. To install a decoder:
- Carefully remove the locomotive body as instructed in the separate technical diagram (if provided) or by gently prying the body from the chassis.
- Locate the PLUX22 interface socket.
- Align the PLUX22 decoder with the socket, ensuring correct orientation, and gently press it into place.
- Replace the locomotive body, ensuring it snaps securely into position without pinching any wires.
Refer to your specific decoder's manual for programming and configuration details.
5. Operating Instructions
5.1 Basic DC Operation
Once the locomotive is on the track and connected to a DC power supply, slowly increase the voltage on your power pack. The locomotive will begin to move. Adjust the voltage to control speed. Reverse the polarity on your power pack to change direction.
5.2 Lighting Functions
The Piko 51606 ET21 features drive-dependent light changes. The headlights will illuminate white in the direction of travel, and the tail lights will illuminate red in the opposite direction. This is automatically controlled.

Figure 3: Angled front view of the Piko 51606 ET21, showcasing the detailed front lights and buffer.
Digitally Switchable Cab Lighting: If a PLUX22 decoder is installed, the cab lighting can be digitally switched on and off using your digital control system. Refer to your decoder's manual for the specific function key assignment.
5.3 Coupling
The locomotive is equipped with NEM Bay + short coupling background. To couple with other rolling stock, ensure the coupling mechanisms are aligned and gently push them together until they engage. To uncouple, lift the rolling stock slightly or use an uncoupling ramp if available.
6. Maintenance
Regular maintenance ensures the smooth and reliable operation of your Piko locomotive.
6.1 Cleaning the Wheels and Track
Dust and dirt can accumulate on the wheels and track, affecting electrical contact and running performance. Use a soft, lint-free cloth or a specialized track cleaning tool to keep both the wheels and track clean. For stubborn dirt, a small amount of isopropyl alcohol can be used on the cloth.
6.2 Lubrication
Periodically, the moving parts of the locomotive (e.g., gears, axles) may require lubrication. Use only specialized model train lubricant. Apply sparingly to designated lubrication points. Over-lubrication can attract dust and hinder performance.
6.3 General Cleaning
Wipe the locomotive body with a soft, dry cloth to remove dust. Avoid using harsh chemicals or abrasive materials, as these can damage the paintwork and delicate details.

Figure 4: Side view of the front section of the Piko 51606 ET21, highlighting the detailed bogie and side grilles.
7. Troubleshooting
If your locomotive is not functioning as expected, consult the following table for common issues and solutions:
| Problem | Possible Cause | Solution |
|---|---|---|
| Locomotive does not move. | No power to track; dirty track/wheels; poor electrical contact. | Check power supply connections; clean track and wheels; ensure locomotive is properly seated on rails. |
| Lights do not work. | No power; damaged LED; incorrect decoder settings (if digital). | Check power; inspect LEDs for damage; verify decoder programming. |
| Erratic running or stalling. | Dirty track/wheels; insufficient lubrication; track imperfections. | Clean track and wheels; apply lubricant sparingly; check track for smooth joints and level surface. |
| Loud or unusual noises. | Lack of lubrication; foreign object in mechanism; damaged gears. | Lubricate moving parts; inspect for obstructions; if noise persists, contact support. |
If you are unable to resolve an issue using this guide, please contact Piko customer support or your retailer.
8. Specifications
| Feature | Detail |
|---|---|
| Model Number | 51606 |
| Brand | Piko |
| Scale | H0 |
| Era | V |
| Length over Buffer | 193 mm |
| Minimum Radius | 358 mm |
| Control System | Direct Current (DC) |
| Digital Decoder Interface | NEM 658 PLUX22 |
| Coupling Style | NEM Bay + short coupling background |
| Lighting | Drive-dependent white/red light change, digitally switchable cab lighting (with PLUX22 decoder) |
| Motor | Five-pole PIKO motor with two flywheels |
| Material | Plastic |
| Recommended Age | 3 years and older (Note: Product is for modeling, not a toy) |

Figure 5: Side view of the rear section of the Piko 51606 ET21, showing the detailed body and bogie.
9. Warranty & Support
For information regarding warranty terms and conditions, please refer to the documentation provided with your purchase or visit the official Piko website. In case of technical issues, missing parts, or other inquiries, please contact your retailer or Piko customer service directly. When contacting support, please have your model number (51606) and proof of purchase readily available.





