Memo to SMH: cut the bollocks

Crikey, just how bad can a newspaper get?

The SMH leads off this morning with an attention grabbing headline of:

Secret plan for return of red rattlers.

The headline itself has almost no connection to the story. The story is all about the proposed re-introduction of single deck trains to the CityRail network (for those of you not from Sydney, we converted to double-deck trains back in the 1960's in order to increase capacity).

The red rattlers were mostly phased out in the early 1990's, with many ending up on farms as a bit of outside accommodation. The rattlers attracted a large following amongst the train-nutter brigade, and many were sorry to see them go. I think the only reason people had an affection for them is that they had been around so long - they were initially introduced in the 1930's when the network was electrified. Whole generations of Sydneysiders had grown up and died during the lifespan of the rattlers. Getting rid of them was as wrenching as demolishing the harbour bridge and replacing it with a rather boring modern looking concrete structure.

The rattlers were still running when I moved to Sydney. I loved them for their freedom. They were sparse, noisy, draughty and yes, they were red (a very dull red, like primer paint). The doors did not close automatically - passengers were supposed to close them when the train moved off. Many opted not to, preferring to travel with the doors open so that you could get a better view, or a bit of breeze in summer. You could hang onto a rail and lean out the door as you went over the Harbour Bridge, which provided a magnificent experience.

The rail corridors were littered with seats from the rattlers, since they simply lifted out, and vandals would open the doors and toss them out by the dozen as the train rattled down the line. The lighting in them was pathetic - you couldn't read a newspaper in them after dark. However, the poor lighting allowed couples to get up to all sorts of funny business, and if you had been out on the turps, the poor lighting and open doors allowed drunks to have a wee out the door. This open door wee policy meant that when the rattlers were finally retired, CityRail discovered that it had an enormous problem with its toilets - it didn't have anywhere near enough on its stations. People were so used to weeing out the door, they'd never needed to use a public toilet, and now suddenly they were forced to.

The rattlers were a bit underpowered, since they featured the original 1930's traction motors still in 1991. The motors were a bit long in the tooth, and overcrowded trains were known to catch fire as they struggled up the steep slope from Wynyard station to the Harbour Bridge with a full load. The motors simply overheated from the strain.

Now, here's the rub. There were two versions of the rattlers - a single deck version and a double deck version, which was introduced a lot later, but it still had the same features - manual doors, the same seats, windows etc, just a double deck. Whilst most people would associate a red rattler with single deck trains, it's not strictly true.

Anyway, the SMH is being disingenious with its headline. We are not seeing the return of museum peices from farmers paddocks. What we might see is the return of single deck rolling stock, built brand new. This is about as sensible as saying, "Obama is getting a black car - so the headline is secret plan for return of Model T Ford".

The idea behind going to single deck trains is that you can cut a lot more doors in the sides to let people on and off - so long as you don't mind getting rid of a lot of seating. "Standing only" type metros can get people on and off really quickly if a carriage has six doors instead of two, but the trade off is a loss of seating. You can't put seats in front of a door. A crammed double deck carriage is a notoriously slow thing to get off - if it is standing room only on both decks, it can take forever to get out of your seat, push past the people standing in the aisle and then get out the door.

However, the other reason why it takes so long to get off a double deck carriage is the sheer number of people it can carry. An 8 car Tangara can carry 2000 people if you really jam them in - that's 250 per carriage. I have no idea what a single deck can carry, but it would have to be less, simply because it would have a lot less floor space - unless you remove all the seats and get most people to stand. But it takes longer to get off a Jumbo jet holding 400 people than a small Airbus holding 80 because five times the number of people have to get off. A single deck train with two doors will take less time to empty than a bigger train with the same number of doors because of the smaller number of passengers.

Hmm, less passenger capacity on a rail network that is currently bursting at the seams. Does this really make sense?

If the per-train capacity is going to fall by say 20-30%, it means they will need to run a lot more trains per hour just to stand still. If you are currently moving 10,000 people per hour from A to B using say 10 trains at 1000 people per train, and you introduce trains that only hold 700 people, then you suddenly need to run 14 trains per hour to carry the equivalent number of people (for those of you that can do maths, I am assuming that 200 people will be carried Indian style on the roof).

Here starts the lesson on train operations from the anorak wearing train spotter.

One of the things that governs the capacity of a length of rail line is the signalling system. Think of a stretch of road through your local CBD - in Sydney, it would be George St. Let's say there are 20 sets of traffic lights between one end of the CBD and the other. Now, imagine that when the lights go green, only one car can go through them into the block ahead. As soon as I drive through the lights, the traffic lights will go red behind me in order to prevent another car from running up my arse. If the road ahead is clear, then the lights will be green ahead of me. If there is a car waiting at the lights two streets ahead, then the next set of lights in front of me will be red - I won't be able to drive into the same city block as a car in front of me (otherwise you get the Glenbrook crash, where one train smacked into the back of another, killing 7).

Now, the capacity of your road through the CBD will be governed by the number of signals. The more signals you have (and thus the closer together they are), the more cars you can jam into that bit of line. Theoretically, you could cut the road up into itty-bitty little sections all about six feet longer than your car, and cram about a thousand cars into that line, but progress might be a bit frustrating during peak hour.

The existing rail network is setup to deal with a certain number of double deck trains. Signals are expensive to build and maintain, and a greater number of them makes the network more complex to manage, and makes life harder for the Train Controllers, so you don't put in more signals than you absolutely need. So if you need to increase the number of trains per hour from 10 to 14, you are going to need more signals.

Don't ask me what a new signal costs, but I am sure you would get stuff all change out of a million dollars. It may in fact cost a lot more. The design process has to be extremely thorough and painstaking - you can't risk having a train with 2000 people on it smacking into another fully loaded train because of poor signal design. There are very few people around the world with that sort of experience, so they are expensive and hard to employ. Signals are tricky to install, since you are installing them close to a working rail line, which has hundred tonne trains rumbling past every few minutes. And it's not just a matter of plopping in a post with coloured lights at the top - the new signal has to interlock with the signals either side of it, and be connected back to a control room which might be 100 kilometres away. The control panel in the control centre needs to be updated with new lights to represent the signal, the Controllers need to be trained and so do the drivers that drive up and down that line.

Training the drivers about a new signal might sound wierd, but trains do not having the braking power of cars, so drivers have to be much more careful about their speed. If they are used to coming around a corner at 80km/h and having a bit of flat, open track in front of them, and suddenly there is a signal at red 200 metres away, they are going to have a problem pulling the train up in time. Especially if there is another train sitting just beyond the red signal. They need to be trained to manage their speed to suit the new track configuration.

All of this is expensive, so it would not surprise me if half the cost of introducing new trains was swallowed by signalling.

The silly buggers will probably forget that they need to increase the electrical capacity of the network, which is what happened when the Milennium trains were introduced. The size of the substations, their spacing and the carrying capacity of the overhead electrical wiring were setup according to the power draw of a certain number of Tangara trains per hour. If you want to run more trains per hour across a certain bit of track, you need to install more substations in order to provide more electricity, and you need to cut the overhead wiring into smaller chunks so that it can handle the current.

My electrical knowledge is crap, but let's assume that a Tangara draws 100 watts of power. If you are running 10 Tangaras down a bit of track, the substations need to be able to provide 1000 watts, and the overhead wiring needs to be able to carry that amount of power without overheating and stretching in summer. If the overhead wiring overheats too much, it stretches too far and sags, and at that point it gets tangled in the pantograph of a train (that's the bit that sticks up and touches the wire, giving the train power). When it gets really hot, trains slow down so that they draw less power, thus reducing the risk of getting tangled up.

The screwup with the Millenium trains is that although they are the same size and have the same carrying capacity, they draw a lot more power - because they have more powerful motors, more bells and whistles etc. If we assume a Millenium train draws 120 watts instead of 100, you can see you've got a problem with running 10 trains per hour if you only have 1000 watts of capacity in the system. It cost CityRail millions to put in more substations etc when they finally woke up and realised that they had to beg Treasury for more money.

Now, we've assumed earlier that you'll require 14 single deck trains to replace 10 double deck trains, and I'd assume that the single deck trains will require only a bit less juice than the double deck trains - let's go with 90 watts instead of 100. Woops, you need 1260 watts of capacity in a network that can only supply 1000.

You get my drift. You can't just dick around with rail systems.