Can You MIG Weld Railroad Track? A Comprehensive Guide

While it is technically possible to MIG weld railroad track, it is not a recommended practice due to the inherent challenges and risks involved. Railroad tracks are made of high-carbon steel, which poses significant welding difficulties, and the resulting weld may not be strong enough to withstand the extreme stresses and loads encountered in railroad applications.

Challenges of MIG Welding Railroad Track

High-Carbon Steel Composition

Railroad tracks are typically composed of high-carbon steel, which is notoriously difficult to weld using electric arc welding processes, including MIG (Metal Inert Gas) welding. The high carbon content in the steel makes it prone to cracking and brittleness, making it challenging to achieve a strong, reliable weld.

Technical Considerations:
– High-carbon steel has a lower thermal conductivity, which means it requires more heat input to achieve proper fusion and penetration during the welding process.
– The high carbon content also increases the risk of weld cracking, as the rapid cooling of the weld can lead to the formation of hard, brittle microstructures.
– Precise control of the welding parameters, such as heat input, travel speed, and shielding gas composition, is crucial to mitigate these issues.

Shock Loads and Stresses

Railroad tracks are subjected to immense shock loads and stresses due to the weight and speed of the trains that traverse them. Even if a successful MIG weld is achieved, the resulting joint may not be strong enough to withstand these extreme conditions.

Technical Considerations:
– Railroad tracks experience a combination of compressive, tensile, and shear stresses, which can cause the weld to fail over time.
– The impact and vibration forces generated by passing trains can also lead to the development of fatigue cracks in the weld, further compromising its integrity.
– Specialized welding techniques, such as multi-pass welding or the use of filler metals with higher strength and toughness, may be required to create a weld that can withstand these demanding conditions.

Preheating and Post-Heating Requirements

Proper preheating and post-heating are critical when welding high-carbon steel to ensure a strong and reliable weld. This requires specialized equipment and precise temperature control, which may not be readily available to a DIY user.

Technical Considerations:
– Preheating the railroad track to a temperature between 250°F and 300°F (120°C and 150°C) can help reduce the risk of weld cracking and improve the overall weld quality.
– Post-heating the weld, followed by a controlled cooling process, is also essential to prevent the formation of hard, brittle microstructures in the heat-affected zone.
– Achieving and maintaining the correct preheating and post-heating temperatures requires specialized equipment, such as induction heaters or resistance heating devices, as well as the knowledge to properly monitor and control the temperature.

Recommended Welding Approach

can you mig weld railroad trackImage source: Mig weld example

If you still wish to attempt MIG welding railroad track, it is essential to use a high-amperage MIG welder and a wire feed speed that can provide sufficient penetration. Additionally, preheating the rail to the recommended temperature range can help improve the weld quality.

Technical Considerations:
– Use a MIG welder with a high amperage output, typically in the range of 300-500 amps, to ensure adequate heat input and penetration.
– Adjust the wire feed speed to match the high amperage, ensuring that the wire is being deposited at a rate that can keep up with the heat input.
– Preheat the railroad track to a temperature between 250°F and 300°F (120°C and 150°C) using specialized heating equipment, such as induction heaters or resistance heating devices.
– Maintain the preheating temperature throughout the welding process to ensure consistent heat input and prevent the formation of hard, brittle microstructures.
– Consider the use of a multi-pass welding technique, where multiple weld beads are deposited to build up the weld thickness and improve its overall strength and toughness.

Alternative Joining Methods

While MIG welding railroad track is not recommended, there are alternative methods for joining railroad track that may be more suitable for a DIY user. These include thermite welding and bolted or mechanical connections.

Thermite Welding

Thermite welding is the method commonly used by railroad companies to join railroad track. This process involves a chemical reaction that melts and fuses the two pieces of metal together, creating a strong and reliable joint.

Technical Considerations:
– Thermite welding requires specialized equipment, such as a thermite welding kit, and precise procedures to ensure a successful weld.
– The process involves preheating the rail ends, pouring the thermite mixture into a mold, and allowing the molten metal to cool and solidify, forming a strong, continuous joint.
– Thermite welding can produce a weld that is as strong or stronger than the original railroad track, making it a suitable option for railroad applications.

Bolted or Mechanical Connections

Another alternative to welding is the use of bolted or mechanical connections, which can provide a strong and reliable joint without the need for welding.

Technical Considerations:
– Bolted connections can be made using specialized rail joint bars, which are designed to span the gap between two rail ends and secure them together using high-strength bolts.
– Mechanical connections, such as those using clamps or other specialized devices, can also be used to join railroad track without the need for welding.
– These types of connections are designed to withstand the shock loads and stresses encountered in railroad applications, making them a viable alternative to welding.


While it is technically possible to MIG weld railroad track, it is not a recommended practice due to the inherent challenges and risks involved. The high-carbon steel composition, the extreme shock loads and stresses, and the specialized preheating and post-heating requirements make MIG welding a challenging and potentially unreliable option for joining railroad track.

If you are considering working on railroad track, it is strongly recommended to explore alternative joining methods, such as thermite welding or bolted/mechanical connections, which are better suited for this application and can provide a stronger, more reliable joint.

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