Agree with you Matthew. But you are comparing chalk with cheese! With 2107 the balance would still be in favour for THAT tram with high accn, rather than low, as would for 980 with high accn rather than low.

Do you really need A/C for a tram in a heritage system? Yes, Sydney does have days of high humidity, but is A/C really necessary at SPER? Most people are still happy to ride on a 1908 design tram like 1111 (?) with wooden seats, noisy gears, jolts from hard suspension, noisy rattles from the various ‘not quite’ alignments in the bogies, etc. Nor do they clamour for A/C on the R and R1 class trams. I would suggest that SPER has more important tasks to spend money on than A/C on a tram ride that is, what 15 min at most?

Ducks for cover and pulls head in.

Regards

Dudley

Sent from Mail for Windows 10

From: Matthew Geier
Sent: 04 July 2020 07:08
To: TramsDownUnder
Subject: Re: [TramsDownUnder] 'Heritage' tram of a different type.

On Sat, 4 Jul 2020 at 04:47, Dudley transitconsult@...> wrote:
Slight misconception , I think.  It takes exactly the same amount of energy to go from zero to 60 kph with an acceleration of 1.3 m/s2, as it does with acceleration of 0.6 m/s2.     In fact, if air and rolling resistance are taken into account, due to the length of time that these are encountered during acceleration, it takes slightly less energy at the higher acceleration.
 
Not just rolling resistance, there are considerable power losses in the old resistance control and the efficiency of series-DC motors vs 3 phase induction motors.
The PCC has starting resistances, gearboxes and a DC motor that at best is 85% efficient. The Variotram has an electronic switching drive that has very low loss, 3 phase induction motors that can be 95% efficient and no gear losses.

I suspect if both were set to the same acceleration rate and tested, the larger Variotram would come out quite a bit ahead of the PCC for maximum demand.
There is about 60 years of technological change in traction control between them. I would expect the field has learned a few things over that time!.

What will be the absolute killer on the 'total KWhr consumed over time will be the 12kw of airconditioning on the Variotram that the PCC doesn't have, 2107's airconditioning currently doesn't work and the quote for overhaul by the OEM means they will be 'ventilate only' for some time as there are other priorities.

You don't want to look at 2107 too closely - the advertising vinyl trapped pockets of water behind it - particular along the panel seams - so there are small spots of corrosion and damaged paintwork all over the car. The ends with their complex curves in fibreglass are covered with score marks were the AOA people cut the vinyl 'in situ' around the curves,

Some bus people told me the AOA covered buses suffer body damage as well and at least one operator tries to rotate the AOA covered buses instead of re-applying new advertising to the same bus each time till its body ends up with actual rust holes in it.

As part of the work on 1014, it had the rust cut out and a new coat of paint, so it's looking really good.