Overview
Double-ended switch bolts are critical components in railway infrastructure, specifically designed for fastening switch points where tracks diverge. Unlike standard bolts, their dual-threaded design allows for secure attachment from both sides, accommodating the dynamic forces present in switch mechanisms. These bolts are engineered to withstand both vertical loads from passing trains and lateral forces during switch operation. Manufactured to exacting railway standards (such as AREMA or EN standards), these bolts typically feature coarse threads for better grip in wooden ties or specialized nuts for concrete sleepers. Their design prevents loosening under vibration, a common challenge in track applications.
Structure and Working Principle
The bolt's symmetrical design features threading along both ends, with an unthreaded shank in the middle section. This configuration allows the bolt to function as a pivot point while maintaining clamping force. The central shank diameter is precisely calibrated to match the clearance holes in switch plates, ensuring proper alignment during installation. When installed, one threaded end secures into the tie (either directly or via an insert), while the opposite end receives a washer and nut. The dual-thread system creates balanced tension, preventing the bolt from working loose under the constant vibration of passing trains. Specialized versions may include anti-rotation features like square necks under the bolt head.
Key Features
High-grade steel construction (typically Grade 8.8 or higher) provides the necessary tensile strength (minimum 800 MPa) to withstand rail forces. Most commercial variants feature hot-dip galvanizing or other corrosion protection, crucial for outdoor railway environments. The threading is often rolled rather than cut, enhancing fatigue resistance. Standard lengths range from 150mm to 300mm, with diameter typically matching rail fastener systems (commonly 22mm or 24mm). Some premium versions incorporate nylon-insert locknuts or prevailing torque features to prevent spontaneous loosening. The bolt heads are usually hexagonal, sized for impact wrench compatibility in field installations.
Application Areas
Primarily used in railway switch (turnout) assemblies, these bolts secure the movable switch rail to either timber or concrete sleepers. They're essential in both mainline and yard switches, particularly in areas requiring frequent train routing changes. Some tram systems and heavy-haul mining railways employ reinforced versions. Beyond railways, similar double-ended bolts see use in heavy machinery where components require pivoting while maintaining clamp load. However, the switch bolt variant is specifically optimized for the unique loading patterns and environmental conditions of trackwork applications.
Maintenance and Precautions
Regular inspection should verify proper torque (typically 300-400 Nm for M24 bolts) and check for thread wear or corrosion. Retightening may be necessary after initial installation as wood ties compress. Use only compatible lubricants on threads - graphite-based products are preferred over petroleum greases in electrified zones. When replacing, always use bolts matching the original specifications to maintain proper clamp force. Never mix different material grades in the same assembly due to galvanic corrosion risks. In coastal or de-icing chemical environments, consider stainless steel versions (grade 304 or 316) despite higher costs.
B2B Procurement Guide
Industrial buyers should specify: material grade (e.g. 8.8, 10.9), coating type, thread specifications (metric coarse is standard), and length. Bulk purchases (typically 100+ units) often qualify for 15-30% discounts. Lead times vary from 2-8 weeks for custom orders. Quality certifications to request include ISO 898-1 for mechanical properties and ASTM A153 for zinc coatings. For critical applications, consider suppliers who provide material test reports. Just-in-time delivery programs are available from major railway suppliers to reduce inventory costs while ensuring availability for maintenance projects.
Related Manufacturers
- 主营：防火栅栏两用门、防水密闭门、防腐枕木、道岔、调度绞车、排型钢梁、钢筋网片、螺纹钢锚杆、避难硐室密闭门、油侵枕木、轨道配件、尖轨、水泥轨枕、压轨器、双速绞车、钻头钻杆、钻机、矿车
- 主营：管道测压泵、电动试压泵、法兰分离器
- 主营：鱼尾双头钢轨棘轮扳、消防器材、电力施工、带电作业工器具
- 主营：游泳圈、挡水板、防汛沙袋、鱼尾双头钢轨棘轮扳、防汛吨袋、扬声喇叭、吸水膨胀袋、阻水防洪袋、电动液压钳、防汛喊话器、高分贝铜锣、铜铝电缆剪线钳
- 主营：防护服、防洪墙、捣固机、鱼尾双头钢轨棘轮扳、电缆架、引虫灯、放线架、缘鞋套、剥皮器、绝缘罩、压油泵、割灌机、导线管、工作服、绝缘鞋、遮蔽罩、切轨机、电工刀、断线剪、防捻器、测试仪、软梯头、汽油锯、削皮刀、绝缘靴、棉大衣
- 主营：鱼尾双头钢轨棘轮扳、带电作业、电力施工、五金机具
- 主营：鱼尾双头钢轨棘轮扳、救灾被子
- 主营：升降平台、绝缘撑杆、引线锁杆、双头锁杆、绝缘横担、杆顶挡板、绝缘锁杆、柱上挂架、电缆支架、四腿放置架、绝缘清洁刷、电缆支撑架、绝缘储物架、安全带悬挂架、绝缘工作平台、绝缘升降横担、高压绝缘挡板
- 主营：检查仪、收紧器、防护服、鱼尾双头钢轨棘轮扳、监测仪、救援靴、隔膜泵、双肩包、三脚架、修剪机、锂电池、除草机、高压泵、液压泵、灭火鞋、三轮车、搜救网、抛绳器、扫描仪、装备绳、应急灯、工作服、照明灯、救援斧、救生衣、排水车
- 主营：鱼尾板、skl弹条、轨距块、磐螺栓t、螺栓定制、普通螺栓、固磐螺栓、地脚螺栓、磐扣件d、扣件wj-2、六角螺母、道钉固磐、绝缘胶结、螺母定制、垫片胶垫、固磐扣件、轨道道钉、铁路胶垫、预埋套管、铁路配件、弹条扣件、橡胶垫片、铁路器材、铁路弹条、绝缘套管
- 主营：振动夯、破切机、管片车、捣固机、报警仪、风煤钻、风筒布、三用阀、减速机、电机车、除雪机、铁水包、振动器、磨轨机、凿毛机、道口板、充气胎、行走轮、封孔器、介质粉、测定仪、传感器、泥浆泵、岔机芯、校正仪
- 主营：矿用设备、铁路设备、救援装备、便携式双头螺栓扳手、防爆电器、路面机械、工程机械
- 主营：矿山机械
- 主营：挖藕机、划线机、劈石机、修剪机、除雪机、铁水包、铜水包、凿岩机、呼吸器、地钻、水带、灭火器、播种机、U型钢支架、高倍数泡沫机、钢筋机械、园林机械、轨道机械、搅拌机、开槽机、矿车、调度绞车、耙斗装岩机
- 主营：花边梁、卷扬机、反光吊带、左开道岔、隧道施工、轨道接头、双钩链条、吊车垫木、支架液压枪、喇叭包胶辊、矿用自救器、弹簧扳道器、轨道防腐枕木、单体支柱柱帽、自救一体装置、单体支柱升柱器、液压支柱防倒带、紧急避险安全门、无压风门、托辊、防火栅栏两用门、避难硐室门
- 主营：槽型绝缘、轨端绝缘、成组绝缘50kg、AT道岔二孔绝缘板、鱼尾螺栓、钢轨绝缘、绝缘管垫、M线卡、U型卡、绝缘垫圈、绝缘管、调高垫板、鱼尾板、绝缘夹板、方刚绝缘、尖端杆绝缘、角钢绝缘、环氧树脂绝缘、绝缘套管、弹条、固线卡、环线卡
- 主营：三环链、拨道机、压轨器、螺栓煤机、鱼尾螺栓、锯齿环、连接环、皮带扣、矿车斗、起道机、挤孔机、18kg手动、轨道器械、电子轨距、螺丝盖帽、轨道焊接、弹条压板、矿车碰头、轨距挡板、钢轨绝缘、调高垫板、轨道交通、轨道工矿、施工工具、单卡双卡
- 主营：轨道固定件、铁路扣件、地铁扣件、道岔、高铁扣件、压轨器、道夹板、铁垫板、鱼尾板、翻轨器、铁路道钉、弹条扣件、轨道压板、轨距拉杆、弹条、轨距挡板、扒钉、橡胶垫板、矿车轮、铁路轨枕、弹条扳手、螺旋道钉、绝缘轨距块、钢轨急救器、挡车器
- 主营：钢结构螺栓、大六角螺栓、热镀锌地脚螺栓、钢结构扭剪螺栓、预埋锚栓、预埋螺丝
- 主营：气动葫芦、液压支架油缸、高速激光熔覆、道岔螺栓道口钉、滑轮滑车、单体液压柱子
- 主营：钢轨、轻轨、重轨、起重机钢轨
- 主营：高速圆钢套丝机、锚固架、电动胀管机、手持式地脚螺栓套丝机、道岔密贴检测锤、钨极磨尖机、钢丝绳芯输送带切割机、输送带剥皮机、法兰分离器、气动钢轨钻孔机、矿用喷射泵、电动试压泵、太阳光土挡灯、TS钨极磨削机、调车员工作服、液力耦合器拉马、气动砸号机、钢丝绳芯输送带剥头机、紧固器、手摇把、手动液压弯排机、钩锁器、扭矩放大器、螺旋合拢器、钢筋轧尖机
- 主营：抓木器、扫地机、捣鼓锤、道岔弹条扳手、炮泥机、升压器、三用阀、马弗炉、减速机、配电箱、测量仪、除雪机、封孔器、粉碎机、轨道杆、动葫芦、化线机、钻孔机、直道机、挖泥船、取样器、切条机、鱼尾板、卷绳器、凿岩机、取样机
- 主营：高位翻车机、烘靴机、洗靴机、螺栓道口钉、喷浆机、给煤机、除铁器、回柱绞车、张紧绞车、电动滚筒、纠偏装置、螺旋千斤顶、手拉葫芦、轴流风机、注浆泵、螺纹钢锚杆、电动坦克、高压清洗机、锚杆钻机、聚能管、硫化机、平板车、锚索搅拌器、搬运气垫、气浮搬运车、喷射器