Critical Rail Fasteners

Hex Bolt.

DIN 931 · 12.9 ,10.9 or 8.8 · M20 × 70

Hex Bolt for subways, light rail, emus and locomotives. Review the product reference, recorded specifications and drawing requirements to identify the configuration needed for your assembly.

Catalogue reference: CF-RT-005

Grade / hardness12.9 ,10.9 or 8.8
Size / designationM20 × 70
Surface treatmentSee parameters
Standard / drawingDIN 931
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Parameters

Technical parameters.

Product technical parameters
ProductHex Bolt
Standard / drawingDIN 931
Grade / hardness12.9 ,10.9 or 8.8
Size / designationM20 × 70
Surface treatmentZinc-aluminium coating (FLZ) or custom finish
Friction coefficient (µ total)0.11–0.18
ApplicationSubways, light rail, EMUs and locomotives
Application recordRecorded since 2012

Confirm the final specification against the order drawing. A recorded application year is not a service-life or warranty statement.

  • The source's '12..9' typographical error is displayed as 12.9; the other listed grades are unchanged.

Product details

Product description.

Rail vehicle fastening.

The product record identifies use across subways, light rail, EMUs and locomotives. Use the named component and its individual specification to locate the part within your vehicle assembly; a shared application category does not make different fasteners interchangeable.

SubwaysLight railEMUsLocomotives

Design basis

The product record cites DIN 931. Include that standard designation and the relevant drawing revision in your inquiry, and identify any order-specific differences. The standard reference does not replace the need to confirm the listed size, required grade and finish. Requirements not stated in this product record should remain subject to drawing confirmation.

Drawing and part reference

Head, shank & thread

Identify the head form, thread designation, overall or under-head length and any fitted-shank or shoulder details from the drawing. Where the product name specifies a flange, drilled hole, special drive or cone neck, include that feature in the part reference. A similar photograph is not enough to establish the same specification.

Configuration to confirm

Finish & assembly conditions

The listed treatment is Zinc-aluminium coating (FLZ) or custom finish. Specify which listed option is required, together with any drawing-defined preparation or inspection requirements. The recorded friction requirement should remain linked to that specification; it is not an installation-torque value. Tightening instructions and acceptance conditions need confirmation for the actual assembly.

Project-specific requirements

Selection guide.

A clear drawing and complete inquiry help distinguish the exact part from another fastener in the same application group.

  • Part reference

    Send the drawing number and revision, or identify the existing component.

  • Dimensions

    Thread, pitch, length and mating dimensions. Mark any special geometry on the drawing.

  • Grade / hardness

    Identify the required listed option and retain its original grade or hardness notation.

  • Surface requirements

    State the required finish and any project-specific friction or inspection requirements.

  • Order scope

    Specify quantity, additional components and your requested delivery date.

Quote catalogue reference CF-RT-005 when contacting us. Related products below are separate catalogue entries, not a pre-approved assembly kit. Please confirm mating parts and final requirements against the assembly drawing.

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Share the application, quantity, material, grade, finish, drawing and delivery target. We will use those details to frame the next technical conversation.

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