The Anonymous Widower

Government Focuses On New Stations And Trains

This is the title of an article in Rail Magazine.

This is the opening paragraph.

Passenger numbers rising fast, new stations, improved facilities and new trains are the result of policies followed by the current Government and not what Labour wants to follow, claims Secretary of State for Transport Chris Grayling.

As an example about what is needed Gayling talks about the Cleethorpres to Sheffield Line.

It is an interesting insight to some of Mr. Grayling’s thinking.

But I agree we need more stations and trains.

I also feel that wit the right innovation and design, we may be able to provide services in places that previously have been thought not to be viable..

January 21, 2017 Posted by | Transport | , , , | 4 Comments

Stonehenge Is Unique

Stonehenge is unique and at the age of ten, I was able to walk amongst the stones in a party from my Primary School.

That was much better than the limited access you get now.

But then in the mid-1950s, Stonehenge didn’t get the visitors it does now.

In The Times today, there are reports of an Almighty row about how traffic is hidden from the monument.

This article on the BBC, which is entitled Stonehenge tunnel ‘should be longer’, puts forward a shorter view of the arguments in The Times.

The real problem with the traffic around Stonehenge, is that something should have been done about it years ago. As with so many problems, successive governments have just ignored the unique site.

I think that any solution to the future of Stonehenge should do the following.

  • Remove all passing traffic as far away as is practical.
  • All visitors to the monument should probably come by electric bus from the a nearby railway station or Park-and-Ride.
  • Improve the rail service on the South Western Main Line, which is not electrified and needs more capacity.

I also feel that modern technology could be used to provide a better view of the stones.

Certainly, what we have at present is totally unacceptable to both road traffic passing the site and visitors.

There is even a proposal for a Wilton Parkway station, which would be on the Wessex Main Line and linked to Stonehenge by bus, that I wrote about in A Station For Stonehenge?

This would provide a Tourist Route from Bristol to Portsmouth via Bath Spa, Stomnehenge, Salisbury and Southampton.

 

January 21, 2017 Posted by | World | , , , | 2 Comments

Class 710 Trains And Regenerative Braking

The new Class 710 trains for the London Overground, will be a next generation train, which could set new standards of energy efficiency. This is from a Bombardier Press release, that the company released when they received the order from London Overground.

The new trains will have similar features to the existing London Overground fleet (also manufactured by Bombardier), including walk-through carriages, air-conditioning and improved accessibility. These next-generation AVENTRA trains will feature an innovative design with optimised performance, including reduced weight, energy consumption, maintenance costs and high reliability, providing substantial benefits to both TfL and its passengers traveling on key London Overground routes, including the newly acquired West Anglia Inner Metro Service.

Note that there is no mention of regenerative braking, but this is mentioned in relation to the other Aventra trains on order; the Class 345 trains for Crossrail.

The Aventra has a slightly unusual and innovative electrical layout.

This article in Global Rail News from 2011, which is entitled Bombardier’s AVENTRA – A new era in train performance, gives some details of the Aventra’s electrical systems. This is said.

AVENTRA can run on both 25kV AC and 750V DC power – the high-efficiency transformers being another area where a heavier component was chosen because, in the long term, it’s cheaper to run. Pairs of cars will run off a common power bus with a converter on one car powering both. The other car can be fitted with power storage devices such as super-capacitors or Lithium-Iron batteries if required.

This was published six years ago, so I suspect Bombardier have improved the concept.

Could it be that the Class 710 trains consists of a two-car power unit sandwiched between two indentical driving cars.

The train could have a formation defined by something like.

DMSO+PMSO+TSO+DMSO or DTSO+PMSO+MSO+DTSO

The cars are as follows.

  • DMSO – Driving Motor Standard Open
  • PMSO – Pantograph Motor Standard Open
  • DTSO – Driving Trailer Standard Open
  • TSO – Trailer Standard Open

I’ve assumed there are a lot of powered axles as there are with the Class 345 train, but an appropriate number of trailer instead of motor cars can be used according to the demands of the route.

Search the Internet for “Class 710 train regenerative braking” and you find nothing official of with provenance.

I don’t believe that the Class 710 trains are not fitted with regenerative braking, as if you want to save energy on an electric train, it is one of the must-have features in the design.

But you need to be able to handle the electrical energy generated under braking.

Normally, the electricity is fed back into the overhead wires or third rail, so that it can be used by another train nearby. This technique is used extensively on the London Underground and third-rail electrification systems. Although, it is used on some 25 KVAC overhead systems like c2c, it means that the braking energy has to be converted to a high voltage to feed the electricity back.

So on the Aventra are Bombardier taking an alternative approach of using onboard energy storage to handle the energy generated by the braking?

Consider.

  • Braking energy generated at a station stop, is immediately available to accelerate the train back to line speed.
  • The onboard energy storage is designed to work with the traction motors.
  • It is irrelevant to the drive system, if power comes from 25 KVAC overhead or 750 VDC third-rail.
  • The overhead or third-rail power supply doesn’t need to be able to handle return currents.
  • The train probably has enough onboard power to get to the next station at all times, should the power supply fail.

But the biggest factor is the amount of energy needed to be handled.

In How Big Would Batteries Need To Be On A Train For Regenerative Braking?, I calculated that the energy of a fully-loaded Class 710 train travelling at 100 kph is around 15 KwH.

So when a train stops, this energy will be released.

To get a better handle on how much energy is involved let’s look at these specifications for a Nissan Leaf car.

Nissan talks about 24 and 30 kWH versions of the car, So if this is the battery size, then one of Nissan’s batteries could store all the braking energy of a four-car Class 710 train.

This sounds absolutely unbelievable, but you can’t argue with the Laws of Physics. or the performance of modern automotive battery technology.

There are five lines, where the new Class 710 trains will run.

  • Gospel Oak to Barking
  • Chingford Branch
  • Liverpool Street to Cheshunt
  • Romford to Upminster
  • Watford DC Line

How many of these lines are setup with the capability of accepting the return currents of regenerative braking?

The question is irrelevant if the Class 710 trains handle their own braking energy.

Conclusion

As the energy of a laden Class 710 train going at line speed is around 15 KwH, which is well within the capability of an automotive battery from a quality electric vehicle, I feel very strongly, that the Class 710 trains will handle regenerative braking using onboard energy storage.

 

 

 

January 21, 2017 Posted by | Transport | , | 4 Comments