How to Maintain Railway Spikes: A Field Guide for Dog Spikes and Screw Spikes

Railway spikes are the workhorse fasteners of timber-sleeper track. A dog spike is driven into the sleeper with its head pressing on the tie plate or rail foot; a screw spike is threaded into a pre-bored hole and grips the timber along its full length. Both types loosen over time under vibration, train load and sleeper aging, so a scheduled maintenance routine is essential to keep gauge, alignment and holding power within design limits.

What the Inspection Should Cover

1. Spike Tightness and Seating

Check that every dog spike head still presses firmly against the tie plate, with no visible gap or rocking. For screw spikes, verify that the threads remain fully embedded in the sleeper and that the head has not backed out. A spike that can be turned by hand or lifted with a claw bar has lost its holding power and must be re-driven or replaced. Pay extra attention to spikes in the gauge corner and at joint locations, where dynamic loads are highest.

2. Sleeper Condition Around the Spike

Wooden sleepers that are cracked, split, decayed at the spike hole or mechanically worn reduce spike holding capacity regardless of the fastener itself. Check for splits running from the spike hole to the sleeper edge, for decayed or spongy timber around the hole, and for enlarged holes where the thread can no longer bite. Damaged sleepers should be renewed or reinforced before new spikes are driven; driving a new spike into a failed hole gives false security.

3. Corrosion and Thread Condition

Rust on the exposed shank, head corrosion and seized threads are common in humid, coastal or chemically aggressive environments. Apply an anti-rust lubricant or rust-converting treatment to the exposed surfaces of screw spikes where the specification allows, and keep the thread clean so that future re-tightening remains possible. Heavily pitted or necked-down spikes should be replaced rather than reused.

4. Coordinate with the Rest of the Fastening System

Spike condition cannot be judged in isolation. Rail pads distribute the wheel load and reduce localised stress on the spike and sleeper; fishplates (joint bars) and rail clips maintain joint stability; rail anchors restrict longitudinal rail movement caused by thermal expansion and braking. A full inspection cycle should therefore cover pads, joints, anchors and spikes together, and any component that is worn should be corrected in the same maintenance window.

Typical Spike Specifications Encountered in Maintenance

Fastener	Common Specifications	Material / Grade	Surface
Dog spike	5/8in x 6in, 9/16in x 5-1/2in, 3/8in x 3-1/2in, 1/2in x 3-1/2in	A3, Q235, 45#, 55#	Plain or coated per project
Screw spike	Ss5, Ss8, Ss25, Ss36, UIC 864-1 series	Q235, 35#, 45#, 40Mn2, 20MnSi	Plain (oiled), black paint, color paint, zinc, hot-dip galvanizing

Strength grades for screw spikes commonly range from 4.6 to 8.8. When ordering replacement spikes, match the grade and the thread form to the original fastening standard so that holding power and hole diameter remain compatible.

Setting Up a Maintenance Cycle

Schedule a full visual inspection of spikes at the same interval as the general track walk-through, and a hands-on tightness check at least once per maintenance cycle.

Inspect more frequently after extreme weather, flood, or heavy haulage campaigns, since timber moisture changes and peak loads accelerate loosening.

Record spike losses, re-driven quantities and sleeper replacements so that problem sections can be identified early.

Keep spare spikes, pilot-hole drill bits and a calibrated torque or driving tool available at the depot.

Frequently Asked Questions

1. How often should railway spikes be checked?

There is no universal interval: it depends on traffic density, axle load, sleeper age and climate. A practical baseline is a visual check on every track patrol and a manual tightness test within each scheduled maintenance cycle; sections with new sleepers or recent re-spiking should be re-checked after the first few weeks because fresh timber seats in.

2. What is the correct way to re-drive a loose dog spike?

Remove the spike, inspect the hole for splitting, and use a pilot hole of the correct diameter if the timber is hard or the old hole has closed. Drive the spike vertically so the head seats squarely on the tie plate, and do not over-drive to the point of crushing the timber.

3. When should a screw spike be replaced instead of re-tightened?

Replace the screw spike when the thread is stripped or corroded, when the head is damaged, or when the sleeper hole is so enlarged that re-tightening no longer restores holding force. Re-tightening a spike with a worn thread can strip the last sound timber and make the problem worse.

4. Does applying lubricant to spikes weaken the fastening?

Anti-rust treatment is applied to the exposed surface and, if specified, to the thread to make future removal easier; it does not reduce the mechanical grip because holding power comes from thread engagement with the timber. Use only products permitted by the track standard, and do not lubricate the interface that must develop friction against the tie plate.

5. Can spike maintenance be combined with other track work?

Yes, and it should be. Spike tightening is most efficient when combined with pad inspection, joint re-tightening and anchor adjustment in the same possession, because access, tools and tamping gangs are already on site and the track geometry can be corrected in one pass.

6. Why do spikes loosen more at rail joints?

Rail joints concentrate dynamic impact and vertical deflection, so the forces transmitted to the fasteners are higher than in plain track. That is why joint-area spikes and the joint bars themselves need the most frequent attention in any maintenance cycle.