The Anonymous Widower

Freight Diesel Traction Realities

The title of this post is the same as that of a comprehensive article by Roger Ford in an article in the April 2019 Edition of Modern Railways.

In the article Roger talks about the problems of decarbonising the freight sector on the UK’s railways.

Future Traction

This section in the article begins with this paragraph

Since the laws of physics and chemistry rule out pure battery or hydrogen fuel cell 3 MegaWatt (4,000 hp) freight locomotives from around 2035 we are going to need to start replacing the diesel locomotives for routes yet to be electrified.

The following actions are suggested.

  • More electrification, through a rolling program.
  • Research into and production of low-CO2 locomotives.
  • 4000 hp locomotives to run faster, longer and heavier freight trains.

These actions will apply to many countries in Europe and the wider world.

Hybrid

This section in the article begins with these two paragraphs.

Extension of electrification will reduce the length of the last miles beyond the end of the wires, making increased use of electric traction viable. Here the challenge will be to provide sufficient diesel traction power and range.  Stadler’s Class 93 ‘tri-mode’ locotive provides an interesting preview.

It builds on the Class 88, which adds a 700kW diesel engine to a 4MW Bo-Bo electric locomotive.

The Class 93 locomotive has a larger 900 kW diesel engine and a lithium titanate oxide battery.

I estimated the battery size at 126 kWH in Stadler’s New Tri-Mode Class 93 Locomotive.

Roger reckons that the battery gives 6-7 ,minutes of power to boost output to 1,740 hp or 1300 kW.

  • The boost from the battery would appear to be 400 kW
  • For 6.5 minutes this would need 43.3 kWH

Either Roger’s 6-7 minutes or my deduced battery size of 126 kWH is wrong. So I will assume both figures are wrong.

Suppose though, you wanted to boost the power of a Class 93 locomotive to the 2,500 kW of a Class 66 locomotive for an hour, which would get a freight train into or out of the Port of Felixstowe.

  • 1600 kW will be needed to boost the diesel engine.
  • 1600 kWH will need to be stored in the battery.
  • I will assume 75 Wh/Kg for the LTO batteries.
  • I have made no allowance for the use of regenerative braking.

This gives a weight of 21.3 tonnes for the batteries.

Roger says this in the article.

If you need to fit diesel engines and batteries into an electric locomotive for freight the a Co-Co configuration gives you another 20 tonnes on a 17.5 tonne axle load.

This leads me to believe that a hybrid locomotive with the power of a Class 66 locomotive and a range of one hour is possible.

 

 

 

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

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