Saint-Gobain Seals’ Rulon® J sliding elements will be utilized on the bogie of the newest 7000 series trains in the Washington DC metropolitan area.
Manufactured by an industrial company in Japan whose expertise includes land, sea, and air transportation systems, the 7000 series cars are considered to be safer and also feature many new elements for riders’ comfort and convenience such as no-slip rubber flooring, ergonomic seating, improved circulation, additional space, LCD information screens and digital signs.
They are the largest series of cars ordered by the city’s transportation agency and will replace all of the old 1000 series cars by 2017 as a result of being much more technologically advanced, eventually composing half the fleet by the end of 2018.
Attached underneath the train cars, a bogie is a key element on the cars carrying the wheelset and suspension and serves a number of purposes:
- Support of the rail vehicle body.
- Stability on both straight and curved tracks.
- Ensuring ride comfort by absorbing vibration and minimizing the impact of centrifugal forces when the train runs on curves at high speed.
- Minimizing generation of track irregularities and rail abrasion.
The purpose of Saint-Gobain Seals’ Rulon® J sliding elements in the bogie of these 7000 series trains is demonstrated when traveling on curved tracks. The bogie frame turns into the curve through the wheels guided by the rails. To allow the bogie to follow the curved track, a degree of movement is required. This movement is supported by the Rulon® J sliding elements, making the train more stable.
As part of their polymer product line, the Rulon® J material was selected due to its very low friction, high resistance to wear and resistance to deformation. Another important feature of the material is its compliance with FST (Flame, Smoke and Toxicity) regulation in accordance with ASTM E662-09 and ASTM E162-11 standards. Because the material performs to ASTM FST flame and smoke standards, it is considered to have flame spread and smoke concentration rates slow enough to give passengers sufficient time to disembark the vehicle more safely.
Rulon® J is a polymeric dull gold PTFE compound and has one of the lowest coefficients of friction of most PTFE compounds, making it ideal to avoid stick-slip and achieve smooth motion.
The Rulon® product line includes a variety of high-performance bearings and components, which meet today's need for enhanced wear performance in a PTFE-based material. Primarily used in mechanical, electrical and chemical applications, Rulon® withstands a variety of harsh environments such as extreme dryness, cryogenic temperatures, water, steam and hydrocarbon fuel. Some applications include ball bearings on the Mars Rover Curiosity, new generation EGR sealing solution for Emission Control Standards Euro 6 & 7, components in harmonic scalpel surgical tooling and bearings on chemical analyzer equipment.