The replica locomotive
The replica locomotive in its present home, the National Waterfront Museum.
Trevithick's Penydarren locomotive and tender at W.I.M.M. in 1983.
Trevithick's Penydarren locomotive and tender at W.I.M.M. in 1983.

The Penydarren loco

On 21 February 1804, the world's first ever railway journey ran 9 miles from the ironworks at Penydarren to the Merthyr-Cardiff Canal, South Wales. It was to be several years before steam locomotion became commercially viable, meaning Richard Trevithick and not George Stephenson was the real father of the railways.

In 1803, Samuel Homfray brought Richard Trevithick to his Penydarren ironworks at Merthyr Tydfil in South Wales. Homfray was interested in the high pressure engines that the Cornishman had developed and installed in his road engines.

He encouraged Trevithick to look into the possibility of converting such an engine into a rail-mounted locomotive to travel over the newly laid tramroad from Penydarren to the canal wharf at Abercynon.

Crawshay's wager

It would appear that Trevithick started work on the locomotive in the autumn of 1803 and, by February 1804, it was completed. Tradition has it that Richard Crawshay, owner of the nearby Cyfarthfa ironworks, was highly sceptical about the new engine, and he and Homfray placed a wager of 500 guineas each with Richard Hill (of the Plymouth ironworks) as to whether or not the engine could haul ten tons of iron to Abercynon, and haul the empty wagons back.

The first run was on 21 February, and was described in some detail by Trevithick:

"...yesterday we proceeded on our journey with the engine, and we carried ten tons of iron in five wagons, and seventy men riding on them the whole of the journey... the engine, while working, went nearly five miles an hour; there was no water put into the boiler from the time we started until our journey's end... the coal consumed was two hundredweight".

Unfortunately, on the return journey a bolt sheared, causing the boiler to leak. The fire then had to be dropped and the engine did not get back to Penydarren until the following day.

This gave Crawshay reason to claim that the run had not been completed as stipulated in the wager, but it is not known if this was ever settled!

The engine was, in fact, too heavy for the rails. Later, it would serve as a stationary engine driving a forge hammer at the Penydarren works.

Replica locomotive

The replica locomotive on display in the Museum today was built working from Trevithick's original documents and plans (now in the National Museum of Science and Industry). It was inaugurated in 1981 and, ironically, presented the exact same problem as the original engine — it too broke the rails on which it ran!

We cannot underestimate the importance of Trevithick's locomotive. In 1800, the fastest a man could travel over land was at a gallop on horseback; a century later, much of the world had an extensive railway system on which trains regularly travelled at speeds of up to sixty miles per hour. This remarkable transformation, a momentous occasion in world history, was initiated in south Wales in that February of 1804.

The Penydarren locomotive - Steaming Days

A short film documenting the yearly steaming of Richard Trevithick's replica locomotive at the National Waterfront Museum, Swansea.


7 February 2020, 11:21
The pennydarren loco is probably in Merthyr Tydfi

john hellin
12 May 2019, 12:58
why does,nt The National Railway Museum at York, have anything on display about the real founder of the railways Richard Trevethic ?
Marc Haynes Amgueddfa Cymru – National Museum Wales Staff
10 May 2019, 10:31

Annwyl Guto Roberts,

Diolch yn fawr am eich ymholiad diweddar ar ein wefan. Gellir prynu copi o’r cynlluniau a ddefnyddiodd yr Amgueddfa i ail-greu Locomotif Penydarren ar ffurf cryno ddisg. Er mwyn cael copi, cysylltwch â fy nghydweithwraig Kay Kays ( os gwelwch yn dda.

Diolch yn fawr,

Tîm Digidol

Guto Roberts
8 May 2019, 17:23
'Rydwi ystyried adeiladu model gweithredol o locomotif stem Richard Trevithick ar raddfa tua 10 gwaith yn llai na'r gwreiddiol. A oes modd cael copi o'r cynlluniau manwl a ddefnyddiodd yr Amgueddfa i adeiladu eich locomotif chi? Gallwn alw yn yr Amgueddfa yn Abertawe neu ddrebyn copi ar bapur drwy'r post neu ei gael ar ebost. Mae fy ngwraig yn perthyn i'r grwp/gymdeithas "Ffrindiau'r Amgueddfa Genedlaethol".


Guto Roberts
Jennifer Protheroe-Jones, Principal Curator – Industry Amgueddfa Cymru – National Museum Wales Staff
4 April 2019, 12:10

Hi Paulo Santos Monteiro and Roy R. Reynolds, no original plans of the Penydarren locomotive survive. The Science Museum in London holds original drawings of Trevithick's locomotive designs of 1803 and 1805 and can supply copies if you contact them. The general arrangement drawing and the suite of detailed drawings of individual components made to enable the building of this Museum’s working conjectural reconstruction of the Penydarren locomotive of 1804 in 1981-2 can be purchased on a CD. If you wish to order a CD, please email Ms Kay Kays, the Museum's Image Licensing Officer ( to enquire about current prices and postage to you.

Albert Ross, the Royal Mint in the UK issued a commemorative £2.00 coin with an image of a Trevithick locomotive on the occasion of the bicententary in 2004.

McM, the original Penydarren locomotive ceased to be used as a locomotive after no more than a few months. After its wheels were removed it was used as a stationary engine to drive machinery in the Penydarren Ironworks for some years. It was later installed as a stationary engine to haul trams up one of the inclines on the surface tramroads that connected iron ore and coal mines to the works. It was scrapped in the 1850s a few years before interest began in locating and possibly recording or preserving the remains of the engine.


Al Grayson
27 February 2019, 18:06
Roy R. Reynolds, you will notice that the Pen-Y-Darren locomotive had plain wheels to run on flanged plate rails. To run on conventional railway track the wheels would need to have flanges. That would be no problem of course.
I notice that you intend to use 7-1/2" gage track. You must be in the USA as the rest of the world, even the NE of the USA, uses 7-1/4" gage for 1-1/2" = 1'-0" 1/8 scale.
Here's wishing you well in your enterprise.
Paulo Santos Monteiro
27 June 2018, 01:38
Hi, I've deep interest and passion about steam machinery, steamboats and steam railway wagon are magical to me. I wish built a scale model of the steaming Richard Trevithick’s Penydarren locomotive for my own Garden Railway. Will be great have access to the copies of the original plans for I can work on this project. Any help will be very much appreciated indeed. Thank you for your time.
Best regards,
Santos Mont.
Albert Ross
16 June 2018, 08:20
The only country to ever give acknowledgement of Trevithicks achievement was the Soviet Union Which issued a postage stamp commemorated the event.
25 October 2017, 03:55
Hi.. Could anyone possibly tell me where the original Trevethic Locomotive'' (Penydarren Locomotive) and what happened to it? Any info would be much appreciated...


18 October 2017, 07:35
How would I go about getting a copy of the plans used to build this reproduction locomotive? I am intrigued with it and would like to build a 7 1//2 inch gauge model of it.

Leave a comment