The Unique story behind Sydney’s Red Sets
Sydney’s red sets have a history like no other in the world. Our suburban train system was developed out of a steam based network of heavy rail vehicles. It also rose at a time when electric traction technology was rapidly changing throughout the world. New products emerged almost daily. Sydney was a very young and rapidly growing metropolis.
The one single reason why the reds served our city for so long was due to the commonsense attitude applied to our network by the Australian engineers who shaped it. Studies into overseas networks were undertaken before designs on Sydney’s rolling stock were finalised. The design of Sydney’s cars was a unique blend between the desire for a “Metro” style system and the existing “English” steam based suburban system with traditional carriages and longitudinal seats.
The result was a practical car which held around 70 seated passengers but also allowed ample room for standees and featured large sliding doors for fast entry and exit. They featured long lasting steel construction and a look which transcends many different design periods.
It’s no wonder that these cars looked as natural in the Sydney landscape of the 1990s when they were withdrawn, as they did in the 1920s. Very few rolling stock designs worldwide can share such a claim.
Just as unique is the design of the electrical technology behind what makes them go and has driven some carriages over three million kilometres in their lifetime, exceeding the distance to the moon and back.
The most striking difference between Sydney’s reds and other electric rolling stock is the “two motors” legacy. A single motor and trailer combination has only two 360HP (200kW) motors on the motor car which are both placed on one bogie. This led to a very fine engineering line between the amount of power available and the amount of traction which could be gained from only two axles lifting 85 tonnes of steel plus passengers up the steep 1 in 30 grades which exist on the network – especially from Wynyard up to peak of the Harbour Bridge.
Without adoption of the “two motor” scheme, Sydney may not have had electric trains at all. This is because the cost would have been so prohibitive to equip the trains in any other way.
The amount saved exceeded 200,000 pounds, equating to hundreds of millions in today’s dollars. To understand the reason why, we must go back in time, well before 1926 when Sydney’s first “red set” ran.
At that time, an extensive network of steam hauled suburban trains already operated. It was using a variety of wooden bodied rolling stock which included a fleet of 101 motor cars built in 1921, to a standard which would allow later conversion to electric.
These existing passenger cars were already equipped with expensive trailer “bogies,” the steel “cradle” assembly which supports the wheels under each carriage end. By adopting a two motor approach, the engineers were able to manufacture only 101 new bogies for these first 101 motor cars because the existing trailer bogies could then be left underneath the other end.
To add to the savings, the 101 trailer bogies displaced by the conversion of these cars were then immediately re-used on the first 101 new motor cars built. The savings were so immense that the two motor option was adopted. However there were a few problems.
Before 1926, only 750 volt traction motors had been built anywhere in the world. The specification for two motors meant that Sydney’s cars required very high powered 1500 volt motors.
At the time they were introduced, Sydney’s electric trains featured the most modern and advanced electrical traction technology anywhere in the world. These were the very first motors in history to utilise 1500 volts directly across a single armature. The motors were also among the first to employ manufacturing methods now considered “essential” in modern electrical design. It’s these same motors that sit under cars 3426 and 3218 on heritage red set F1 today.
But the Australian innovation didn’t stop there. The switchgear controlling the motors was also of a revolutionary, modular electro – pneumatic design. An eight car single deck train accelerating from Wynyard over the Harbour Bridge requires more than one million watts of power. In 1926 this was enormous for a suburban car set with no separate locomotive. It amounted to over 250kW per car – far more than the largest electric locomotives in manufacture at the time.
It’s a small wonder Sydney’s red sets had little trouble keeping 1990s timetables alongside modern Trains, long after similar vintage rolling stock around the world had been shunted to the big carriage shed in the sky.
The Sydney single deckers were originally designed to use cast iron brake shoes. However it was discovered that these shoes wore down too quickly and left dust everywhere. By the 1950’s, they were replaced by a newer “Composite” brake shoe. It’s these which give F1 that classic, distinctive “Sydney Train” smell which many would instantly recognise whenever the driver of F1 applies the brakes today.
Unfortunately though, it was also found that the new shoes also “polished” the driving wheels too much. This caused even more problems with the very limited traction ability of the single deck two motor cars.
The polished wheels have led to the classic “Single decker wheelslip” which often turns many rail fans crazier than their car mad counterparts at drag strip raceways. It makes a red set journey in wet weather a truly memorable experience for any traction fan. Sydney’s Single Deckers were (and still are) a full sensory experience!
The problem of the “two motor saga” persisted for decades in Sydney until eventually the rail authorities got sick and tired of the red sets slipping to a stand on steep grades and then requiring rescue. Something just had to be done.
Not to be outdone, the argument to adopt “four motors” continued. It was finally addressed in the late ’60s with the commencement of the “7000” programme. Here, a selection of existing “two motor” cars were converted to four motors. Heading this development was car C7500, known as “Moss’s Rocket” which was named after the electrical engineer who supervised the project : Geoff Moss. Geoff now assists “Historic Electric Traction” in the restoration and maintenance of Red Set F1 here in 2017.
The ultimate aim of the “7000” project was to produce enough “four motor” cars to place one or two in each eight car set. This aim was reached in the early 1980s. It contributed significantly to the retention of the cars in traffic until 1992 as they now became as reliable and capable as more modern trains. Car 7396 in Set F1 is a “7000” series, 4 motor car, originally converted from Car 3396 back in 1968.
Another important change which occurred in the 1970s was the progressive disabling of the “weak field” notch (sort of like an overdrive speed) in the red sets. This happened because of a parts shortage.
By the ’70s, the original 1920’s vintage switchgear was becoming difficult to maintain There were insufficient switch units to allow all the cars to be maintained. The removal of weak fields freed up four switch modules per car. The second hand switches were then reconditioned and re-used as spares in lieu of new ones which were no longer manufactured.
Unfortunately this resulted in a lower maximum speed. However inclusion of the four motor “7000” series cars in consists went some way to compensating for the loss of weak fields. Today, Red Set F1 operates with three motor cars and one trailer, giving it more than enough grunt get out of any sticky situation it might find itself in. It also means that even with no weak fields, Set F1 can still turn a very decent speed and keep up with all of the latest rolling stock.