TB/T 2628 Railway Crane Design Standard Requirements
TB/T 2628, the "General Design Specification for Railway Cranes," is an industry-recommended standard governing the complete design of railway cranes. It covers key technical requirements including overall layout, structural design, mechanism selection, electrical systems, and safety protection systems, and applies to the design development and type testing of rail-mounted railway cranes.
TB/T 2628 serves as the foundational technical specification for railway crane design in China. Developed under the leadership of the China Academy of Railway Sciences, it applies to railway cranes operating on standard-gauge tracks. Unlike general purpose bridge crane design standards, this specification accounts for the unique operating conditions of railway cranes, including railway clearance constraints, track alignment and profile conditions, subgrade bearing capacity, and coupled operation with rolling stock. Kelude Heavy Industry strictly adheres to TB/T 2628 as the design baseline in its railway crane development, ensuring that products meet the operational safety and reliability requirements of railway systems.
Overall Layout and Clearance Constraints
The standard sets explicit requirements for the overall layout of railway cranes. The complete machine envelope must comply with the rolling stock clearance limits specified in GB 146.1, with no component's outermost point encroaching on the clearance profile while on straight track. For the connection between the car body and bogies, the standard recommends a combined side bearing and center pivot load-carrying structure, with side bearing clearance controlled within the 2–4 mm range.
Regarding axle load distribution, the standard requires that the axle load deviation of any single axle under full-load conditions not exceed ±4% of the average axle load, ensuring uniform load distribution along the track. For multi-axle bogies, the standard also specifies stiffness matching principles for the primary and secondary suspensions, recommending a vertical equivalent stiffness ratio between 1:3 and 1:5 to balance ride stability and curve negotiation capability.
Structural Design Highlights
TB/T 2628 adopts a limit state method framework for the steel structure design of railway cranes. Primary load-bearing members must be verified against fatigue strength, with the fatigue design load spectrum derived from load frequency distribution data statistically collected from actual service operations. The standard specifically requires that critical joint areas—including the boom root hinge brackets, the slewing bearing seat on the turntable, and outrigger box structures—undergo stress analysis using the finite element method, accounting for the effects of weld geometric stress concentration.
For material selection, the standard recommends Q345qD or Q370qE bridge structural steel for primary load-bearing structures, with low-temperature impact toughness meeting the requirement of KV₂(-40°C) ≥ 47J. For components such as the boom that experience significant dynamic loads, the standard further imposes supplementary fatigue crack growth rate limits to ensure no fatigue failure occurs within the 25-year design life.
Mechanism Selection and Performance Parameters
The hoisting mechanism is the core working mechanism of a railway crane. The standard requires that railway cranes with a rated lifting capacity of ≥100 t be equipped with a dual-drum hoisting system, with the two drums linked via a synchronous shaft or electronically synchronized control. The recommended hoisting speed range is 0.5–3.0 m/min at rated load, which may increase to above 6.0 m/min under no-load conditions. The slewing mechanism must adopt a hydraulic motor drive with a normally closed brake, offering continuously adjustable slewing speeds from 0.1 to 0.5 r/min.
The outrigger system is critical to operational stability. The standard mandates that railway cranes be fitted with a four-outrigger extension support system, with each outrigger's maximum bearing capacity designed at 1.5 times the rated outrigger reaction force. The hydraulic lock valve on each outrigger cylinder must comply with ISO 4413, ensuring reliable locking in the event of a hose burst. The standard also requires outrigger extension status detection switches, which interlock to prevent hoisting and slewing operations unless all outriggers are fully extended.
Electrical and Safety Protection Systems
The electrical system design must comply with the requirements of TB/T 3021, "Electrical Equipment for Railway Rolling Stock." The standard specifies that the control system adopt a dual-circuit redundant design, with the main controller and standby controller monitoring each other via hardware watchdog timers. The load moment limiter (LML) must perform real-time acquisition of boom angle, radius, and load data, issuing an early warning signal when the actual load reaches 90% of the rated load, and automatically cutting off hoisting and luffing motions when it reaches 110%.
For safety protection, the standard requires the installation of an anemometer (alarm setpoint 13.8 m/s, automatic shutdown setpoint 20.7 m/s), an anti-overturning load moment limiter, outrigger settlement monitoring devices, and a lighting system for nighttime operations. When working in electrified railway sections, the crane must also maintain the required safety clearance from overhead catenary lines, with the minimum distance between the highest point of the boom and live catenary components being no less than 2 m.
| design elements | TB/T 2628requirements | design basis | verification method |
|---|---|---|---|
| boom cross-section type | box type/Usection profile | FEA Optimization+buckling analysis | 1:5scaled model Stress Test |
| Slewing Bearing | three-row roller type | DIN ISO 281 Rolling bearings — Dynamic load ratings and rating lifelife calculation | overturning moment Test Benchverification |
| Outrigger Span | ≥1.5times Track Gauge / Rail Gauge | most unfavorableoperating conditionssupport reaction calculation | actual vehicle Outriggerload Test |
| Hoisting mechanism | double Hoist Winch+Synchronization Control | ISO 4301 Crane Design Standard Hoisting mechanismdesign | 1.25times Dynamic Load Test |
| Cabin / Operator Cabnoise | ≤85dB(A) | GB/T 25685 | sound level meter Aweighted measurement |
| Electrical Protection | IP54and Above | GB/T 4208 | Dustproof Waterproof Testverification |
| Inspectionitem | Inspection Standard | Inspectionfrequency | acceptance criteria |
|---|---|---|---|
| Static load test | 1.25multiples of rated load | Type Test/factory | no permanent Deformation |
| Dynamic Load Test | 1.1multiples of rated load | Type Test/factory | normal operation without abnormality |
| stability test | 1.25times+wind load | Type Test | no overturning |
| Outriggersettlement | ≤3mm/30min | factory test | hydraulic lock valveeffective pressure holding |
| gauge inspection | GB 146.1 | factory test | no gauge intrusion |
| Load moment limiter (LML)calibration | Accuracy±5% | factory+annual Inspection | over110%automatic shutdown |
Frequently Asked Questions
Q: Which railway cranes does the TB/T 2628 standard apply to?
A: The standard applies to self-propelled railway cranes operating on standard-gauge (1435 mm) tracks, covering models with a rated lifting capacity from 60 t to 160 t. It does not cover road-rail cranes or track-mounted cranes used exclusively for fixed operations within rail yards. For precise applicability, refer to Chapters 1 and 4 of the standard.
Q: What are the key design considerations for a railway crane boom?
A: Boom design focuses on three critical areas: buckling stability, which requires both linear and nonlinear buckling analysis; fatigue strength, where the fatigue life of critical weld seams must be verified against the measured load spectrum; and gauge envelope compliance, ensuring the boom's coverage across its full luffing range stays within railway clearance limits. TB/T 2628 specifies clear technical requirements for all three aspects.
Q: What specific requirements does TB/T 2628 impose on the load moment limiter?
A: The standard mandates a three-stage early warning system for the load moment limiter: a yellow warning at 90% of rated load, an audible and visual alarm at 100%, and automatic cutoff of hoisting and luffing motions at 110%. The system must also include a black-box data recorder that stores the most recent 1,000 operating cycles, capturing lifting capacity, radius, boom angle, and timestamps.
Q: Which tests are required during the factory acceptance test of a railway crane?
A: The factory acceptance test must include at minimum: a static load test at 1.25 times the rated load (held for 10 minutes with no permanent deformation), a dynamic load test at 1.1 times the rated load (three full cycles of each mechanism), an outrigger settlement test under pressure (settlement ≤3 mm over 30 minutes), a gauge clearance check, load moment limiter accuracy verification (within ±5%), and functional tests of all safety devices.
