The Anonymous Widower

Why Are Abellio Starting Norwich-in-Ninety With Class 755 Trains?

At the May timetable change Abellio Greater Anglia will be running four trains per day between London and Norwich in ninety minutes.

I have read that this is possible with the current Class 90 locomotive /Mark 3 coach train sets and that is a fall-back position.

I was also told by a former employee of Greater Anglia, that one night, he was a passenger between Norwich station and Illford depot in an empty Class 321 train, that achieved an incredible time.

So why take the risk with untried Class 755 trains on the first day of the new timetable?

  • Abellio must be very sure that the trains will perform, as they say in the brochure.
  • They also know all the publicity that running new trains will bring.

But could Abellio just want to check the public’s reaction to these trains with effectively a locomotive in the middle, before they decide on the 125 mph bi-mode trains for the Midland Main Line?

I don’t believe that building a 125 mph version of Class 755 train would be beyond the bounds of possibility.

The Weight Of A Class 755 Train

I haven’t been able to do my energy calculation for a Class 755 train, as I can’t find the weight of a Class 755 train on the Internet.

However, I can estimate the weight of a four-car Class 755/4 train from the Stadler data sheet for the train.

This gives the following.

  • Mean Acceleration Electric (0-40 mph) – 1.1 metres/second squared
  • Maximum traction – 200 kN
  • 202 seats and 27 tip-up seats

I think it is reasonable to assume that the acceleration rate is for a train with a typical load of passengers.

Using Omni’s Acceleration Calculator, this gives a time of 16.256 seconds to accelerate from 0-40 mph.

Then putting this time into Omni’s Newton’s Second Law Calculator, gives a train mass of 181.8 tonnes.

As passengers can weigh around twenty tonnes, if they weigh 90 Kg each, with baggage, bikes and buggies, I would estimate that an empty Class 755/4 train weighs around 160-170 tonnes.

By comparison.

I don’t think a figure of 160-170 tonnes is out of line, with a figure of 180 tonnes for a typical loaded train.

Remember too, that these trains are Stadler FLIRTs, where FLIRT is Fast Light Intercity and Regional Train.

Applying Omni’s Kinetic Energy Calculator, gives these figures for the kinetic energy of a train.

  • 90 mph – 40 kWh
  • 100 mph – 50 kWh
  • 125 mph – 78 kWh

As some electric FLIRTs can nun at 125 mph, I believe that a bi-mode FLIRT, based on the Class 755 train could be designed with these characteristics.

  • 125 mph on electric power
  • 125 mph on diesel power

Acceleration on diesel to 125 mph would probably be the biggest problem and it is likely that more power than for a Class 755 train will be needed.

Do Abellio Greater Anglia’s initial Norwich-in-Ninety trains give a clue in that they will be two four-car Class 755 trains working as an eight-car train?

  • It will be eight passenger cars and two power cars at the 25% and 75% positions in the formation.
  • Stadler have built the similar Stadler GTW with two power cars in a single train.

So I suspect that Stadler know the dynamics of these trains very well.

I wouldn’t be surprised if someone told me, that Stadler had offered a bi-mode Stadler FLIRT with two power cars, for the Midland Main Line.

  • The power car concept has been sold to operators with diesel, electric and battery power options.
  • Stadler are proposing to use battery power in the Class 93 locomotive to boost performance.
  • Many would believe, as I do, that hydrogen power could be added to a Stadler power car.

So are these runs at 100 mph with two four-car Class 755 trains, a final trial of the technology to prove that similar higher-powered trains could run at 125 mph on the Midland Main Line, before Abellio sign a contract?

April 21, 2019 - Posted by | Transport | , , , , ,

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