For the benfit of TransLink, the definition of an articulated car.

TransLink is mistakenly calling the new Mk.3 SkyTrain cars articulated, they are not. What Bombardier has designed is a saloon car, gangwayed at both ends; to fit between a married trainset, enabling to make the trainset longer; articulated they are not.

Sad to say, TransLink’s planning staff do not understand the basics, such as “what is an articulated rail car”, yet they are allowed to plan multi billion dollar transit lines, without question.

A Bombardier articulated tram. Notice how the two end sections are supported by the centre section,

which does away with the need for two more bogies or trucks.

Articulated cars are rail vehicles which consist of a number of cars which are semi-permanently attached to each other and share common Jacobs bogies or axles and/or have car elements without axles suspended by the neighbouring car elements. They are much longer than single passenger cars. Because of the difficulty and cost of separating each car from the next, they are operated as a single unit, often called a trainset.

Passenger cars

Articulated passenger cars are becoming increasingly common in Europe and the US. The passageways between the car elements are permanently attached. There is a safety benefit claimed that if the train derails, it is less likely to jackknife and modern construction techniques prevent telescoping.

Articulated cars are not however a new idea. Many railways in Britain during the first half of the 20th century frequently rebuilt older, shorter cars into articulated sets, and the Great Northern Railway in Britain built suburban car sets new. In the 1930s, a number of streamlined trains built for the London and North Eastern Railway also made use of articulated technology.

Freight cars

Manufacturers such as Gunderson make articulated, low-floor “well” cars, articulated trailer carriers and articulated autoracks.

Advantages and disadvantages

Articulated cars have a number of advantages. They save on the total number of wheels and bogies, reducing initial cost, weight, noise, vibration and maintenance expenses. Further, movement between passenger cars is safer and easier than with traditional designs.

Disadvantages primarily relate to lesser operational flexibility. For example, additional cars cannot readily be added to an articulated trainset to accommodate peaks in traffic volume and a mechanical malfunction in one car or power unit can disable an entire trainset. Furthermore the axle load is higher compared to conventional train sets due to the reduced number of wheels and bogies

An articulated diesel railcar. Again notice how the two end sections are supported by the diesel motor unit,

negating the need fro two bogies or trucks.