[MOC] English Electric GT3

[Hod Carrier]

I know it looks like a steam loco but I promise you that it's not.

This is the English Electric GT3, a gas turbine prototype locomotive designed, built and tested as a private venture. Unlike earlier gas turbine prototypes running in the UK (the Brown Boveri 18000 and the Metropolitan Vickers 18100) which used gas turbines to generate electrical power for traction motors, GT3 was built as a prototype to explore the use of a mechanical transmission with a gas turbine to provide motive power.

The project was overseen by J.O.P. Hughes of the English Electric company and was the culmination of 13 years of testing and development. Everything from the characteristics of the gas turbine to the performance of the auxiliaries was novel and each system required exhaustive testing to ensure that they would perform reliably. The loco appeared initially in semi-complete form during 1958 and underwent trials and testing at British Railways Locomotive Testing Station at Rugby before being returned to English Electric for completion.

GT3 then reappeared during 1961 sporting a semi-streamlined body finished in russet brown with Brunswick green frames, wheels, doors and other details. Nicknamed "The Chocolate Zephyr" by rail enthusiasts, GT3 produced 2750hp and could operate at speeds up to 90mph. Mainline testing showed that GT3 was a capable locomotive and could easily match or exceed the performance of the new 2000hp classes of diesel-electric locomotives and the larger steam classes. Although there were some technical difficulties, particularly with the reversing gear, GT3 never failed to complete a test run, even over the most demanding routes and the heaviest loads.

In spite of showing good promise, by the end of 1961 British Railways withdrew it's support for the test program and the loco was returned to English Electric. Following recovery of the gas turbine and associated equipment, what remained of GT3 was scrapped in 1965. GT3 never hauled a passenger service.

My model is probably fairly conventional in terms of it's construction. About the only aspects of note are the floating middle axle under the tender and the fact that the square section of the loco body means that it can contain the power, control and drive which should help give reasonable adhesion. However, the size does mean that running on R40s would be out of the question.

By the way, apologies to anyone clicking through expecting to see some manner of sports car. 

Edited January 29, 2021 by Hod Carrier

[zephyr1934]

What a fantastic build of a very unusual locomotive (great nickname though, grin)

[bogieman]

Beautifully done. What was the fuel?

I love your hook and buffer!

[Hod Carrier]

@zephyr1934 Ha ha!! I thought you'd appreciate the nickname. Thanks must go to you for the custom rods which really complete the look. 

@bogieman Modern aviation jets use kerosene, but a gas turbine can run on pretty much anything that will burn. I believe GT3 burnt diesel as that was what most readily available on the railways at that time. The buffers are as close to oval as LEGO will allow, but the dummy three-link coupler is a technique I have seen used elsewhere which I have copied.

[Brickwolf]

Another exotic prototype but instantly recognizable, super details!

[CDM]

Another great one. The subtle taper at the nose is really well done. The gray piping...is that Lego official? I ask because I'm interested in finding substitute piping for future MOCs.

[Hod Carrier]

Thanks everyone for the kind words.

14 hours ago, CDM said:

The gray piping...is that Lego official?

Yes I believe so. It's 3mm rigid hose bought through Bricklink, so I'm assuming it's an official part. I did have to heat it slightly over a flame to get the 90 degree bend, though.

[Capparezza]

What a strange thing, this GT3 . Chocolate brown makes me crave for something sweet now, hehe. Nice rendition and a proper build, really digging it. Thanks for showing!

[Hod Carrier]

3 hours ago, Capparezza said:

Chocolate brown makes me crave for something sweet now, hehe.

Go for it, my friend. 

3 hours ago, Capparezza said:

Nice rendition and a proper build, really digging it. Thanks for showing!

You're most welcome. Thank you for the kind words.

[Pdaitabird]

Nice work! The GT3 has always been one of my favorite experimental locomotives (probably because it looks so much like a steam engine) and you've captured it well. 

[Hod Carrier]

@Pdaitabird Thank you so much. 

[Tube Map Central]

It's a fantastic representation.

As for the original, what was its fuel consumption? In my reading about the previous two prototypes they performed well and had potential but this was at the cost of gobbling up fuel like nothing seen before of British Railways.

[Paperinik77pk]

Wow!!! Great and "futuristic" (for the time) locomotive - I love these experiments!

You gave it a smooth (and sweet - it seems a chocolate snack!!!) body - absolutely stunning work with round bricks!!! Nice buffers!

I really love it - it is sincerely something I would like to see in a Museum...pity it's not possible. But you gave it the right credit it deserves!!!

Ciao!

Davide

[Hod Carrier]

3 hours ago, Tube Map Central said:

It's a fantastic representation.

As for the original, what was its fuel consumption? In my reading about the previous two prototypes they performed well and had potential but this was at the cost of gobbling up fuel like nothing seen before of British Railways.

Thank you for the wonderful feedback.

The quoted fuel consumption figure for GT3 at full power was 0.635lb/hp/hr, which is not an everyday measure of consumption, while consumption at idle was 20% of this. The designer, J.O.P. Hughes, admitted that GT3's fuel efficiency was not regarded as good enough as it suffers from the same issue that afflicted the previous two gas turbine prototypes, which is that a gas turbine is most efficient when it is working at full power. Thermal efficiency for the unit powering GT3 was 22% at full power dropping to 17% at half power. This is a disadvantage for railway use because trains are often driven on a partial throttle. However, all three of these prototypes were using what might charitably be referred to as 1st generation gas turbines and that advances in gas turbine technology could have yielded better thermal efficiency with it's consequent improvement in fuel consumption.

The railways in the UK didn't see another gas turbine until the experimental APT-E of the 1970s, but this used a different approach. Instead of one large gas turbine, APT-E used a total of eight smaller gas turbines so that the effect of partial throttle could be replicated by using only the number of turbines required at full throttle to generate the amount of power needed for propelling the train.

2 hours ago, Paperinik77pk said:

Wow!!! Great and "futuristic" (for the time) locomotive - I love these experiments!

You gave it a smooth (and sweet - it seems a chocolate snack!!!) body - absolutely stunning work with round bricks!!! Nice buffers!

I really love it - it is sincerely something I would like to see in a Museum...pity it's not possible. But you gave it the right credit it deserves!!!

Thank you, Davide. I must admit that I am a fan of the way it looks too. It's futuristic but in a restrained manner befitting the British temperament.

It's certain that GT3 is not very well known, even within the UK. I had no idea until I chanced on a photo of it at the Institute of Locomotive Engineers exhibition at Marylebone in London and thought "what is that?!" Once I'd done some research and found more images and a history I decided that I just had to build it.