Specialty Stainless Steel / Cromgard - Applications of Cromgard in the Railway Industry by Crompion International

Topics Covered

Background
     Choosing the Optimal Material
     Facts About Specialty Stainless Steels
     Specialty Stainless Steel Increasing in Popularity
     Applications of Specialty Stainless Steel in the Railway Industry
Examples of Where Specialty Stainless Steel is Used in the Railway Industry
     Trams
     Rail Freight – Coal Wagons
     Passenger Rail
     Overhead Electrification – Cantilever Supports
     Ticket Machines
     Rail Sleepers
     Rail Vehicle Wash Systems
     Rail Masts
Third Rail Electrification
The Future
Standards
Summary

Background

Material used in rolling stock construction and the manufacture of infrastructure within the rail industry play an important part in the achievement of increased service life, lower environmental impact, higher safety standards and minimum maintenance.

Choosing the Optimal Material

The problem is few materials offer optimum performance in all of these key areas. Some offer strength, but have poor corrosion resistance, others offer both strength and corrosion resistance but add considerable weight, some offer multiple advantages but add significant cost to the vehicle. Designers need to select materials which maximise value and operational advantage.

Facts About Specialty Stainless Steels

  • Cromgard is 30% stronger than stainless steel
  • Up to 250x more corrosion resistant than mild steel
  • 3x times more wet abrasion resistant than mild steel
  • It’s competitively priced in between stainless and mild
  • If you’re looking for an alternative to stainless or to replace carbon steel, Cromgard is your material of choice.

Specialty Stainless Steel Increasing in Popularity

Increasingly, specialty stainless steels like Cromgard, which conform to EN 10088-2 1.4003 and ASTM A240 UNS S41003, are being chosen as an optimum material for the following applications.

Applications of Specialty Stainless Steel in the Railway Industry

Rolling stock construction:

  • Rail doors
  • Outer skinning/cladding
  • Structural frames
  • Sub-frames
  • Flooring
  • Walls
  • Tanks
  • Freight hoppers.

Infrastructure:

  • Overhead cantilevers
  • Conductor rails
  • Trackside enclosures
  • Ticket/control enclosures.

Benefits of Specialty Stainless Steels to the Railway Industry

Users of specialty stainless steels are now extending financial planning horizons when they consider maintenance and replacement. True cost of ownership comparisons between several candidate materials - mild steel, conventional stainless and specialty stainless steel have repeatedly shown that replacement periods can be extended by as much as ten years with specialty stainless steels’ such as Cromgard - a dramatic reduction in overall lifecycle cost.

Examples of Where Specialty Stainless Steel is Used in the Railway Industry

Trams

As town centres look to solutions to traffic congestion, specialty stainless steel can be found at the core of a revolutionary design in tram which is challenging traditional urban transport thinking and offering users significantly lower costs, weight and energy consumption in comparison with other systems currently available.

Trams, designed and built by a UK manufacturer, have used specialty stainless steel since beginning production of their vehicles in 1997. The decision to use stainless steel for the space frame, interior panels and large external skirt of the vehicles was based on the durability, strength and corrosion resistance of this stainless steel.

Rail Freight – Coal Wagons

Focusing on rail freight applications. A recent inspection of coal wagons, operated by a UK company and built in specialty stainless steel, proved that it can provide a projected ultra-long service life and require minimal maintenance. On inspection of a typical vehicle from the fleet, completely built in specialty stainless steel in 1994/5, the hopper doors were found to be in a bright, smooth condition. No discernable metal loss could be detected and the operator's view was that the wear rate was consistent with the 40-year life expectancy required.

Additionally, specialty stainless steel was chosen for its resistance to corrosion and abrasion, and its inherent strength (allowing the construction of robust structures at relatively low weight) in the design of coal cars for a US company, where the high sulphur content of the cargo is particularly aggressive to coal car interiors.

Passenger Rail

New generation passenger trains built in Germany utilize specialty stainless steel conforming to EN 10088-2 1.4003 for their construction. Their lightweight and low maintenance construction has been helped by the application of 12% Chromium stainless steel for various parts of its construction, specifically flooring, support beams and wall sections between carriages.

specialty stainless steel was selected for its weight saving, low cost and maintenance free advantages. The corrosion resistance of specialty stainless steel which is around 200 times greater than mild steel in atmospheric conditions - has been a further contributing factor to low maintenance features.

Overhead Electrification – Cantilever Supports

Over a decade ago, a field trial designed to test the suitability of specialty stainless steel for the manufacture of overhead cantilever supports for rail electrical conductor equipment was started at a location in the South East of England. The use of specialty stainless steel was designed to demonstrate its corrosion resistance as well as its life cycle cost benefits in this type of application.

The subsequent independent laboratory metallurgical examination of a section of cantilever tubes manufactured in specialty stainless steel, installed on an electrified line at Dovercourt station, near to the port of Harwich in the UK, has confirmed that this material is in excellent condition. Tests were conducted to look for signs of pitting, cracking, stress corrosion or metal loss or deterioration of any kind and the results indicate that specialty stainless steel can withstand attack from all elements causing deterioration.

The site was selected specifically because it is in an exposed position with the sea only yards away, making an ideal laboratory to put a trial material to the most severe test of coastal climatic conditions.

The economic advantages of the specialty stainless steel cantilever system are potentially significant - negligible maintenance service life, lower installed cost because there is less material usage and no corrosion treatment is necessary.

Ticket Machines

Location: platforms at all original stations, some undercover, some at open stations.

Several ticket machines for the Manchester Metrolink, installed in 1994, located on open stations, in suburban districts, exposed to all weathers and more importantly, vandals and abuse, were inspected after five years service. Inspection showed that they had exceeded expectations in terms of corrosion prevention and strength. Where original paint had chipped, scratched or worn, the specialty stainless steel could been seen to be bright and unaffected.

Overall the condition, appearance and performance of the specialty stainless steel in this application was viewed by Metrolink to be excellent. Their experience had show that the steel was giving a potential service life well beyond that expected and was relatively maintenance free. It had maintained an acceptable appearance in a most difficult environment.

Rail Sleepers

Rail sleeper housings containing High Performance Switch Actuators are now manufactured in specialty stainless steel, providing a secure, corrosion resistant environment for this critical rail management equipment.

The system, which provides a complete, integrated switching and crossing mechanism compatible with all known signalling systems use specialty stainless steel conforming to EN 10088-2 1.4003 and ASTM A240 UNS S41003 is a tough, but low cost material that would meet the anti-corrosion demands of this critical application.

Designed for a 25-year service life, the system requirements called for robust design and tough corrosion protection, so stainless steel was essential. Specialty stainless steel, was able to provide the corrosion protection and offer significant cost saving advantages. The specially formed section is produced from ½” thick material.

Rail Vehicle Wash Systems

The structural strength, longevity and minimal maintenance of specialty stainless steel has been cited as the reasons for its use in the automated railway carriage washing units.

Automated units are of the 'drive through' variety, similar to giant car wash units, and are being made by a French company. The original design called for a painted carbon steel structure, however, due to the customers demand for a virtually maintenance free unit, specialty stainless steel was demanded.

Spiral welded tube, made from specialty stainless steel, was reformed from a round to a square section and used as columns and trusses for the structure. The sections were then bound together with specialty stainless steel cold formed channel purlins. The whole unit can be operated by two people and a train of coaches up to 820 feet in length can be cleaned in one operation. The system has been built to allow for future expansion.

With negligible maintenance, specialty stainless steel is allowing capital and operating savings with longer service life for these high value units.

Rail Masts

A visual inspection was conducted March 2003 of electrification masts, manufactured from specialty stainless steel, erected along the railway line between Port Elizabeth harbor and North End in South Africa. The railway line runs along the coast and is constantly exposed to sea spray during windy conditions.

The spot selected for the inspection is the nearest point to the sea, approximately 130 feet. In addition, there are various factories such as paints and chemical nearby, which may add to the corrosive environment.

The masts were erected in 1982 and are required to give maintenance free service for 40 years.

The previously documented inspection was carried out in January 1993. During this inspection some general discoloration was reported particularly on the seaward side. Ten years later we find general “brown” overall discoloration equally on both landward and seaward sides. Tooling marks from the cold forming of the channel were still clearly evident.

Inspection of the welds found no indication of preferential attack in spite of the fact that they were not given any post weld treatment in pickling and passivation.

Inspection of sheared edges found no appreciable difference as the masts are generally evenly discolored with no significant corrosion evident at all.

The only concern expressed was the cracking of the concrete plinths caused by the carbon steel re-bar corroding inside the concrete. However, re-bar is now available in specialty stainless steel and would eliminate the problem completely.

Third Rail Electrification

The recent extension of the Vancouver Skytrain light railway has utilised specialty stainless steel, in the make up of electrified third rails. The material, conforming to EN 10088-2 1,4003 and ASTM A240 UNS S41003, was selected for its resistance to corrosion and electrical and mechanical damage.

This energy-saving conductor rail, designed with a specialty stainless steel surface attached to an aluminum core, is used to provide power for third-rail electrification systems the world over, and benefits from the low weight and increased conductivity of aluminum with the wear resistance of specialty stainless steel.

This project is one of a long list that includes the London Underground Jubilee line and Singapore and Taipei Metro’s, dating back to 1989.

Steels used in railway applications are subjected to some of the most aggressive conditions possible, particularly those near marine and industrial zones, where there is a high degree of atmospheric pollution. The rail is also subjected to electrical wear and mechanical wear from vehicle shoe gear in contact with the conductor rail.

The conventional material used for this application was low carbon steel, but this suffered from corrosion in the atmosphere, and wears at a greater rate than aluminum. Following extensive corrosion trials specialty stainless steel was selected, in comparison to other stainless steels tested, specialty stainless steel exhibited less corrosion when used in close proximity to aluminum. It also offered high electrical conductivity, extended life expectancy and a competitive price.

The Future

Specialty stainless steel provided an excellent cost effective material for the design and build of rail equipment through the eighties and nineties. Today with ever decreasing demands for structural integrity a new product, Cromgard, picks up the baton from 3CR12. As with 3CR12, Cromgard, has excellent corrosion resistant, mechanical and fabrication properties, with the added benefit of specification to international standards.

Standards

Cromgard, has been developed to meet the requirements of:

  • ASTM A240 UNS S41003
  • ASME IIa UNS S41003
  • EN 10088-2 1.4003, and
  • EN 10028-7 1.4003

Summary

Cromgard continues to provide the benefits of corrosion and corrosion/abrasion resistance, easy fabrication and excellent strength, together with its proven low cost and long term price stability. With over twenty years proven record on the world’s roads, Cromgard picks up the benefits of 12% Chromium specialty stainless steels as the optimum choice for vehicle manufacture for the future.

About Crompion International

Crompion International are a Louisiana-based, globally operational world leader in providing specialty, low nickel steels and consulting services to a broad range of industries. As the world's leading manufacturer and distributor of Cromgard, high-performance stainless steel products, Crompion International pride their services not only on selling this specialty product, but on understanding how their customers use their products.

In addition, through patented technologies developed with strategic partners, Crompion International have established the company as an innovative force that is helping to dramatically evolve the industries that it serves.

Crompion International offers a range of specialized stainless steel solutions that can help you lower costs, extend the life of your equipment, reduce maintenance and decrease the weight of your end product. Cromgard, Crompion International's signature stainless steel, offers strength and durability along with amazing corrosion and abrasion resistance.

This company now offer a range of new grades of Cromgard, providing two primary solutions: to improve performance over early grade 400-series where higher temperatures and corrosion are common, and to provide an alternative to price-volatile, high-nickel stainless like 300-series.

This information has been sourced, reviewed and adapted from materials provided by Crompion International.

For more information on this source, please visit Crompion International.

Date Added: Aug 3, 2005 | Updated: Aug 2, 2013
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