Policy Direction Set: Electrification Retrofit Enters Large-Scale Implementation Phase
The formal implementation of the Supervision and Management Measures for the Phasing-out and Renewal of Old-Type Railway Diesel Locomotives by the National Railway Administration has charted a clear path for electrification retrofits: locomotives not yet reaching scrap age with retrofit value can achieve new energy transformation through power source replacement, meeting core indicators of “safety, reliability, intelligence, and greenness.” The equipment renewal action plan jointly issued by 13 ministries, including the Ministry of Transport, further mandates accelerating the “oil-to-electric” upgrade of old diesel locomotives, with policy dividends rapidly unlocking technological potential. Data from China State Railway Group shows that among 7,800 retrofit-eligible diesel locomotives nationwide, nearly 15% have initiated electrification retrofit processes, with the retrofit rate projected to increase to 30 units per month by 2025.
Three Core Technology Breakthroughs Solve Retrofit Challenges
1. Customized Adaptation of Power Battery Systems
Lithium iron phosphate batteries have become the mainstream choice, with their safety and adaptability validated across multiple scenarios: retrofitted locomotives in Yidu, Hubei, adopt 210.56 kWh battery packs, achieving 120 km range; CRRC Dalian’s 1000 kW-class locomotive optimizes liquid cooling technology to boost charging power to 680 kW, achieving full charge in 70 minutes. Technological innovations for extreme environments are more groundbreaking—the CKD6H locomotive exported to Kazakhstan operates stably at -50°C extreme cold through a quadruple protection design, with charge-discharge cycle life exceeding 8,000 cycles. The “modular battery rack” technology employed in retrofits enables installation without structural modification to the locomotive body, with load-bearing deviation of single battery racks controlled within ±2% to ensure axle load parameters comply with original locomotive standards. Lithium iron phosphate batteries have become the mainstream choice, with their safety and adaptability validated across multiple scenarios: retrofitted locomotives in Yidu, Hubei adopt 210.56 kWh battery packs, achieving 120 km range; CRRC Dalian’s 1000 kW-class locomotive optimizes liquid cooling technology to boost charging power to 680 kW, achieving full charge in 70 minutes. Technological innovations for extreme environments are more groundbreaking—the CKD6H locomotive exported to Kazakhstan operates stably at -50°C extreme cold through quadruple protection design, with charge-discharge cycle life exceeding 8,000 cycles. The “modular battery rack” technology employed in retrofits enables installation without structural modification to the locomotive body, with load-bearing deviation of single battery racks controlled within ±2% to ensure axle load parameters comply with original locomotive standards.
2. Efficient Matching and Reconstruction of Power Systems
The core challenge cracked by Lince Group’s research team lies in the coordinated control between battery power and traction systems. The retrofit adopts a “permanent magnet motor + intelligent converter” combination, raising traditional diesel locomotive mechanical transmission efficiency from 82% to 94%. Taking the Dongfeng 7C locomotive retrofit as an example, an adaptive load algorithm enables intelligent switching between pure electric drive during shunting operations and hybrid boost during climbing, achieving 65% braking energy recovery efficiency and reducing power consumption per shunting operation by 62% compared to prototype fuel costs. Notably, CRRC Dalian locomotives achieve 99% compatibility between charging modules and new energy vehicle charging piles, significantly reducing user supporting facility investment.
3. Full-Dimension Upgrade of Safety Protection Systems3. Full-Dimension Upgrade of Safety Protection Systems
Safety pain points of old locomotive retrofits are resolved one by one: the car body adopts a triple anti-corrosion process of sandblasting rust removal + epoxy primer + fluorocarbon topcoat, achieving 10-year rust prevention life in salt spray environments; battery compartments are equipped with dual smoke and temperature detection systems and automatic fire suppression devices, with thermal runaway response time ≤3 seconds; all electrical wiring is replaced with high-low temperature resistant flame-retardant cables, connectors adopt silver-plated terminal crimping processes, and insulation resistance is boosted to above 500 MΩ. The intelligent diagnostic system developed by CRRC Ziyang can monitor 168 battery parameters in real time, providing 48-hour advance warning of single-cell battery degradation risks, reducing retrofitted locomotive failure rates by 92% compared to prototypes.
Typical Cases: Technical Practices from Mountain Branch Lines to International Markets
Domestic Demonstration: Short-Haul Freight Retrofit Model in Yidu, Hubei
The “oil-to-electric” practice on the Song-Yi Railway has become a benchmark for branch line railway transformation. On this line’s 65 km mountain section, nine original diesel locomotives consumed 1.428 million liters of diesel annually, emitting 3,777 tons of CO₂ with maintenance costs exceeding ten million yuan. After the first retrofitted locomotive was deployed, monthly electricity costs were only 1,200 yuan, 60% lower than fuel costs, with a single 6-hour charge meeting full-day construction traction needs. Driver Chen Qiu’s experience intuitively demonstrates the changes: “Cab noise dropped from 95 dB to 62 dB, oil contamination problems are completely solved, and traction force still reaches 100 tons under air conditioning operation.” Currently, retrofitting of a second main locomotive is underway, with battery capacity upgrading to 2,295 kWh and traction weight breaking through 5,000 tons, projected to achieve an annual emission reduction of 487 tons with two locomotives.
Overseas Breakthrough: Technology Export to Central Asia’s Extreme Cold Environment
CRRC Ziyang’s CKD6H locomotive, exported to Kazakhstan, marks the first overseas implementation of China’s new energy locomotive standards. This hybrid locomotive, equipped with an EU IIIA standard diesel engine and a lithium iron phosphate battery pack, achieves 45% fuel savings and an annual CO₂ reduction of 240 tons. Tailored for the wind-sand and extreme cold environments of Central Asian steppes, it adopts sealed battery compartments and low-temperature preheating technology, with a startup time ≤3 minutes at -40°C, and has entered the batch delivery stage after passing EAC certification. This project drives the export of China’s new energy locomotive standard system, with retrofit cooperation intentions already reached with three Belt and Road countries.CRRC Ziyang’s CKD6H locomotive, exported to Kazakhstan, marks the first overseas implementation of China’s new energy locomotive standards. This hybrid locomotive, equipped with an EU IIIA standard diesel engine and a lithium iron phosphate battery pack, achieves 45% fuel savings and an annual CO₂ reduction of 240 tons. Tailored for the wind-sand and extreme cold environments of Central Asian steppes, it adopts sealed battery compartments and low-temperature preheating technology, with a startup time ≤3 minutes at -40°C, and has entered the batch delivery stage after passing EAC certification. This project drives the export of China’s new energy locomotive standard system, with retrofit cooperation intentions already reached with three Belt and Road countries.
Supporting System Construction: Dual Support from Charging Network and Standards System
Charging facility construction is accelerating simultaneously. Charging stations built by State Grid Yidu Power Supply Company along the Song-Yi Railway adopt a “scan-to-charge + intelligent billing” mode, with single-pile power reaching 120 kW to meet rotational charging needs for three locomotives. The National Railway Administration has clarified retrofit technical specifications: original locomotive speed grades and axle load parameters must be retained, bogies must not undergo structural modification, retrofitted locomotives must be marked with the “-EV” designation, and braking distance must be ≤10% shorter than prototypes. CRRC Dalian, Ziyang, and other enterprises have built retrofit solutions covering 200 kW-3000 kW full power range, adaptable to shunting, freight, plateau, and multiple other scenarios.
Technical Evolution Direction: Deep Integration of Intelligence and Connectivity
Next-generation electrification retrofits are already emerging: the 5G + edge computing system being tested by CRRC Dalian enables coordinated energy scheduling for locomotive fleets, reducing cluster operation energy consumption by a further 15%; digital twin-based virtual commissioning technology compresses retrofit cycles from 3 months to 45 days; pilot application of sodium batteries in shunting locomotives reduces battery costs by 30% and further improves low-temperature performance by 20%. Industry forecasts indicate that by 2030, China’s railway freight locomotive electrification rate will exceed 40%, with the retrofit market size surpassing 20 billion yuan.
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