Adhesives enhance new railcar design

French company CFD (Compagnie des Chemins de Fer Départementaux) and its subsidiary companies, have a 120-year history, in designing and building railway rolling stock such as locomotives, carriages, railcars and even rack-railway units.

In 1999, when CFD was commissioned by Le Blanc Argent (railway operator for the Central France region) to design five new railcars on a modernization programme for the regional express (TER) line between Salbris and Luçay-le-Mâle, the weight was a key issue. The trains would then be running on metre-gauge track and there would be a weight limit of 8 tonnes on each of the six axles (compared with 17 tonnes per axle for France’s TGV high-speed train).

To keep the weight down, CFD sought lightweight alternatives to metal wherever possible. As well as bringing engineering advantages, plastic materials can also prove aesthetically superior. For example, CFD’s groundbreaking use of ultra-lightweight polyester panels for the railcar interior produces a bright, modern appearance in perfect keeping with the functionality and image of this means of transport.

To fit the large panels (2 m high by 1.5 m to 3.5 m wide), CFD opted for the Dual-LockTM double-sided adhesive system from 3M, an unobtrusive, reclosable fastening solution that is eminently suitable for the lightweight polyester material and perfectly consistent with the railcar’s sleek interior design.

From a manufacturing point of view, the Dual-Lock fixing system saves a great deal of time (no holes to drill, no screws to fit, greatly simplified fittings inventory), and gives a neater finish than traditional laminated panels.

The Dual Lock fastener is made up of push-fit interlocking male and female strips, one bonded to the painted metal frame of the railcar and the other fitted in a pre-moulded groove in the panel.

The fastening is invisible once the panels are in place, which makes for an uncluttered finish and deters vandalism, since there is no obvious way of removing the panel (screws are notoriously prone to removal).

The Dual Lock system is insensitive to vibration, offering enhanced soundproofing so that passengers enjoy a quieter, more comfortable ride. And the panels can be removed and refitted easily, for convenient maintenance.

The five new railcars should come into service in early 2003, on completion of approval tests by French rail authority SNCF. But CFD already plans to extend the 3M™ Dual Lock™ fastening system to the panels in its forthcoming passenger carriages.

3M and Dual Lock are registered trademarks of the 3M Company.