Dual-Machine Linkage Drives Intelligent Manufacturing | 32-Ton One-Control-Two Double-Girder Crane With Hook Empowers Lean Production at Dalian Locomotive & Rolling Stock Works

As the “cradle” of China’s rail transit equipment manufacturing industry, CRRC Dalian Locomotive & Rolling Stock Co., Ltd. (hereinafter referred to as “Dalian Locomotive & Rolling Stock Works”) has been deeply involved in locomotive R&D and manufacturing for over a century. Its locomotive carriages are renowned both domestically and internationally for their high reliability and precision. In the upgraded production of the new generation of locomotive carriages, traditional lifting equipment struggles to meet the demands of long-distance, large-tonnage, and high-precision collaborative lifting. To address this, Dalian Locomotive & Rolling Stock Works partnered with our company to customize a 32-ton hook double-girder crane with a “one-control-two” linkage system, precisely breaking through production bottlenecks and injecting core power into the intelligent manufacturing of rail transit equipment.

Project Background: New Lifting Challenges for a Century-Old Factory

The locomotive carriage production workshop at Dalian Locomotive & Rolling Stock Works encompasses three core processes: welding, painting, and final assembly. A single locomotive carriage weighs approximately 28 tons and is over 20 meters long. In the inter-process transfer and final assembly docking stages, multiple industry-level hoisting challenges are encountered:

Extremely stringent coordination requirements: A single crane cannot balance the stress points of long carriages, easily leading to carriage tilting and deformation. Traditional two-crane manual coordination methods suffer from poor synchronization, low error tolerance, and are difficult to adapt to modern production rhythms.

Extremely high precision standards: During final assembly, the docking gap between the carriage and the bogie must be controlled to the millimeter level, placing extreme demands on the crane’s micro-speed control and positioning accuracy.

High-frequency, high-intensity operations: The workshop operates on a 24-hour, three-shift system, requiring continuous and stable crane operation, posing a significant challenge to the equipment’s structural strength, durability, and safety protection capabilities.

Clear compliance requirements: As a core manufacturing enterprise for rail transit, the equipment must comply with national special equipment safety standards and be compatible with the workshop’s existing track layout and intelligent production system.

Based on this, Dalian Locomotive & Rolling Stock Works proposed a core requirement: to create a 32-ton “one-control-two” linkage hoisting system to achieve synchronous and precise control of two double-girder cranes, balancing operational efficiency, safety protection, and production flexibility.

Customized Solution: One-Control-Two-Linkage System, Precisely Matching Intelligent Manufacturing Needs

Addressing the production pain points and core demands of Dalian Locomotive & Rolling Stock Plant, our company assembled a dedicated technical team to conduct in-depth research into the workshop’s operating conditions and tailor-made a “one-control-two” integrated solution for the 32-ton hook double-girder crane. This solution achieves full-dimensional customization and adaptation, from hardware configuration and intelligent control to safety protection.

Core Hardware: Heavy-Duty Structure, Solid Foundation for Intelligent Manufacturing

Both 32-ton hook double-girder cranes utilize Q345B low-alloy high-strength steel box-type main beam structures. After overall annealing stress relief treatment and 100% non-destructive testing, welding deformation and residual stress are effectively avoided, ensuring no main beam deflection during long-term, high-frequency operation under a 32-ton rated load.

The hoisting mechanism is equipped with a hardened gear reducer and dual brake motors. The main hook has a rated lifting capacity of 32 tons, and the auxiliary hook has a rated lifting capacity of 10 tons, meeting the dual needs of main carriage lifting and auxiliary component lifting. To address the long dimensions of the locomotive carriages, a custom-designed equalizing beam lifting device is used. Through a four-point flexible connection, it ensures uniform stress distribution on the carriages, preventing structural deformation and surface scratches during lifting.

Core Control: One-to-Two Linkage, Unlocking Synchronization Precision

The system is equipped with an industrial-grade high-performance PLC controller and a dedicated synchronization control algorithm, achieving the core function of **”one person, one control, two machines synchronized”**. Operators can simultaneously lift, travel, and traverse the two cranes from a customized linkage control room, with synchronization errors controlled within ±1mm.

Equipped with a multi-segment variable frequency speed control system, the lifting speed can be adjusted from 0.5-8m/min, the trolley travel speed from 0-40m/min, and the trolley travel speed from 0-20m/min, precisely adapting to the stability requirements of carriage transfer and the high precision requirements of final assembly docking. Simultaneously, the system supports one-click switching between “linkage-independent” modes. When one machine requires maintenance, the other can operate independently, ensuring uninterrupted production.

Safety Protection: Multiple Redundancies Safeguarding Production Safety

Adhering to the safety management standards of Dalian Locomotive & Rolling Stock Plant, the system constructs a five-layer safety protection system to achieve comprehensive risk control:

Load Protection: Equipped with a high-precision lifting capacity limiter, automatically alarming and cutting off power in case of overload;

Synchronization Protection: When the synchronization deviation between the two machines exceeds the threshold, the system automatically decelerates and stops;

Positioning Protection: Both the trolley and crane are equipped with absolute travel limiters and anti-collision buffers to avoid equipment collisions;

Personnel Protection: The control room is equipped with emergency escape devices and audible and visual alarms; the crane is equipped with anti-disengagement devices and a video monitoring system;

Emergency Protection: Configured with a dual-power switching device, allowing for safe hook lowering through the emergency system in case of sudden power failure.

Project Implementation: Lean Management, Remarkable Results

After on-site installation, commissioning, and personnel training, this 32-ton “one-control-two” hook double-girder crane system was officially put into use in the locomotive carriage production workshop of Dalian Locomotive & Rolling Stock Plant in 2020, quickly integrating into the entire production process and achieving significant application results.

Significantly Increased Production Efficiency

The “one-control-two” linkage model completely replaced traditional manual collaborative operations, reducing the inter-process transfer time for a single locomotive car from 25 minutes to 12 minutes, and increasing final assembly docking efficiency by 65%. The workshop’s locomotive car production rate increased from 2 cars per day to 3.5 cars per day, with annual capacity increasing by 75%, helping Dalian Locomotive & Rolling Stock Works successfully complete the delivery of multiple overseas locomotive orders.

Continuously Optimized Product Quality

Synchronous and precise lifting and millimeter-level positioning accuracy effectively avoided tilting and deformation problems during car lifting, increasing the final assembly docking qualification rate from 92% to 100%. The application of a dedicated equalizing beam lifting tool reduced the surface scratch rate of the car by 90%, further ensuring the quality of the locomotive products leaving the factory.

Significantly Reduced Operation and Maintenance Costs

The integrated linkage system reduces the number of hoisting operators by 50%. The dual braking and wear-resistant component design increases the equipment’s mean time between failures (MTBF) to 8000 hours, and reduces maintenance costs by 30% compared to traditional equipment, significantly optimizing the workshop’s production cost structure.

Prominent Industry Demonstration Effect

This project has become a benchmark case for “intelligent hoisting” in the rail transit equipment manufacturing field. Its “one-control-two” linkage technology solution provides valuable reference for hoisting upgrades in other locomotive manufacturing enterprises in China. A relevant person in charge of Dalian Locomotive & Rolling Stock Plant stated: “This customized hoisting system perfectly solves our long-standing problem of collaborative hoisting, not only improving production efficiency but also strengthening safety measures, serving as a crucial support for our intelligent manufacturing upgrade.”

Conclusion

Starting from the production needs of a century-old locomotive plant and addressing industry pain points with customized technology solutions, the successful application of our 32-ton “one-control-two” hook double-girder crane once again demonstrates the value of deep integration between industrial hoisting equipment and lean manufacturing. In the future, we will continue to focus on the field of rail transit equipment manufacturing, and help China’s rail transit equipment intelligent manufacturing reach a higher level with more intelligent and reliable hoisting solutions.