SENTINEL DOUBLE LOCOMOTIVE works number 4612 of 1926 and rebuilt in 1928.
The original model was scratch built by Jan Jarvis and completed and detailed by Geoff Evans. It is built of plastic card for 32mm gauge and has battery radio control with soundcard.
The order for 6412 by Kettering Iron & Coal was made in 1926. It was planned that this modern locomotive would replace old locomotives - Black Hawthorn's dating from 1879/1885 and Manning Wardle's dating from 1889/1897/1906. The Sentinel, rated at 160HP, with boiler pressure at 230lbs/inch and classified 4w+4wTG, an articulated "twin" loco, with at the front, a vertical 2 cylinder steam engine 6 3/4 x 9 inch stroke, with normal speed achieved at 500 rpm. There was a central water tank and the boiler was located in the cab [each loco had its own engine/water/boiler] wheels 1ft-8inch diameter on 3ft gauge track. Each locomotive had its own regulator so the driver would face forward whichever way the engine travelled, but only one reverser. All the controls were coupled together, and both boilers were close enough to be fired by one man - the driver! A second crew man was there for coupling/uncoupling, etc.
6412 was delivered to site October 1926. However it did not come up to expectations being underpowered. The steam engines were originally mounted within the body and drove by chains direct to the front axle, which was connected to the rear axle by an outside chain.
The locomotive was returned to the factory in 1928 for a rebuild. The engines were raised up and a layshaft incorporated to reduce the gearing. The engine connected by chain to the layshaft which was chain connected to the rear axle and outside chain drive to the front axle. Still the locomotive did not perform well and was relegated to shunting duties around the furnaces, until cut up for scrap in March 1960. Perhaps the Kettering loco fleet number 13 did not help!
The order for 6412 by Kettering Iron & Coal was made in 1926. It was planned that this modern locomotive would replace old locomotives - Black Hawthorn's dating from 1879/1885 and Manning Wardle's dating from 1889/1897/1906. The Sentinel, rated at 160HP, with boiler pressure at 230lbs/inch and classified 4w+4wTG, an articulated "twin" loco, with at the front, a vertical 2 cylinder steam engine 6 3/4 x 9 inch stroke, with normal speed achieved at 500 rpm. There was a central water tank and the boiler was located in the cab [each loco had its own engine/water/boiler] wheels 1ft-8inch diameter on 3ft gauge track. Each locomotive had its own regulator so the driver would face forward whichever way the engine travelled, but only one reverser. All the controls were coupled together, and both boilers were close enough to be fired by one man - the driver! A second crew man was there for coupling/uncoupling, etc.
6412 was delivered to site October 1926. However it did not come up to expectations being underpowered. The steam engines were originally mounted within the body and drove by chains direct to the front axle, which was connected to the rear axle by an outside chain.
The locomotive was returned to the factory in 1928 for a rebuild. The engines were raised up and a layshaft incorporated to reduce the gearing. The engine connected by chain to the layshaft which was chain connected to the rear axle and outside chain drive to the front axle. Still the locomotive did not perform well and was relegated to shunting duties around the furnaces, until cut up for scrap in March 1960. Perhaps the Kettering loco fleet number 13 did not help!
Building the Model.
The basic bodies of the models were built by Dan Jarvis, another member of the Merioneth Railway Society who passed away some years ago. The model was not complete but the build quality was so good and near to scale that it could not be discarded and had to be finished.
I sourced new all-metal chassis and 'Como' electric motor drives from Essel Engineering, together with 2.4MHz radio control equipment [Planet T5], Viper electronic Loco speed controller & Mylocosound steam - pump - whistle sound card. Each chassis has an electric motor drive, geared to one axle and twin belt drive to the other axle, one chassis carries the electronics and the other has the rechargeable battery pack. Both chassis have 8 ohm mini speakers to simulate engine sounds [not very accurately I have to admit]. The chassis are interconnected with a 6-core cable.
I started investigating the details of this locomotive by e-mailing Sydney Leleux. He had taken a number of published photographs of the locomotive in about 1960, just before it was scrapped. Sydney kindly provided some copies of more pictures he had taken. He also introduced me to friends of his who had been on visits to the Kettering Furnaces site. Roger West had taken measurements of 6412 and produced a scale drawing, a copy of which he kindly sent me. Unfortunately, at the time of Roger's visit in December 1958, the loco was in the back of a shed with access only to one side and the ends.
The interiors of the model cabs had been started by Dan but were incomplete, being based on a photograph then available of the footplate of a 100HP in "Sentinel Patent Locomotives" originally published by Sentinel Waggon Works in 1931 and republished in 1974 by new owners, Rolls Royce. No pictures of the interior of 6412 were then generally available.
The model locomotive was first exhibited in November 2014, but with the subsequent publication of "Vertical Boiler Locomotives & Railmotors in Great Britain, Volume Two" by Philip J. Ashforth & Vic Bradley with the actual 6412 cab interior picture, the errors of our previous assumptions showed up. That started a new search for more detail through the good offices of the Industrial Locomotive Society. They were very helpful, providing more photographs and referred me to the Sentinel Drivers Club who hold copies of Sentinel works drawings. The amazing thing was the archivist, Richard Nixon lived in the same village as me, Aston Clinton! Richard could not have been more helpful; he perused, with me the collection of drawings held on his computer and identified those which would assist me with my project.
All I had to do now was to amend what had been built previously! It is not always easy to break up a model that took such effort to build in the first place, but that had to be done. The old boilers were stripped out and discarded and new ones built based on the drawings to hand. I was not familiar with Sentinel boiler engineering so every opportunity was taken to peer into Sentinel lorry cabs! I am sure some of the drivers, all very kind & accommodating must have thought I was mad. The only trouble was, the interior of a steam lorry cab is not easy to photograph and many of the critical fittings I wanted to see were shrouded to protect the crew!
New boilers were fabricated in plastic sheet with various cast white metal fittings, available to railway modellers altered and fitted to represent the arrangement on 6412. I would appreciate if experts in such matters do not look too closely at my efforts! The water sight gauges as purchased were too long, so I cut out the white metal parts that were supposed to represent the sight glasses and substituted clear plastic with the edges painted 'brass' for the frames. The twin regulators and single reversing lever were made of plastic and brass. The caps to the chimneys were formed of brass with working operating arms extending down the chimneys. Pipes were formed with various sections of brass & copper wire. Lagging was fine string bound around the 'pipes'.
One detail of 6412 which had puzzled me, and many others was the rodding on one side of the locomotive as seen in various photographs. All other construction details tended to be the same for each locomotive but the rodding showed on only one side of the locomotive when coupled. Many theories were advanced by others, but it was John Hutchings who first ascertained for me their correct function. Surprisingly for an industrial locomotive, the rodding operated water jets washing the rear wheels. Presumably the locomotive working into quarries got a build-up of dust on the wheels requiring removal.
All the historical photographs of 6412 are in black & white so no clue on livery. There are faint traces of the lining in some of the later pictures of the rebuilt locomotive. There are works pictures of the original locomotive as it left the works in 1926 and also in 1928. These show quite ornate lining [for an industrial loco] in 1926 but simpler lining in 1928. Fortunately when Roger did his measured survey he saw the original livery where the Sentinel plate had been removed. He told me: "The shade was very near the light green used by the then countrywide Tilling Group to paint its buses in the 1940/50's. This might be the old pre-WW2 BS 381 C standard colour 218 Grass Green". He also noted the lining - "A broadish black line edged off white both sides ... but the upper front of the cab was not lined".
The lining was the first I have ever attempted on a model. Waterslide transfers were obtained from Rail-Road to the correct pattern. The use of a North West Short Lines "Chopper" guillotine ensured the mitres were all cut to 45 degrees! It was then a case of patiently working around the model one side at a time and leaving overnight to dry before attempting the other side.
I am going to be bold and say the model is complete! If any further information comes to light that contradicts the above then ...... thank you and good night!
I sourced new all-metal chassis and 'Como' electric motor drives from Essel Engineering, together with 2.4MHz radio control equipment [Planet T5], Viper electronic Loco speed controller & Mylocosound steam - pump - whistle sound card. Each chassis has an electric motor drive, geared to one axle and twin belt drive to the other axle, one chassis carries the electronics and the other has the rechargeable battery pack. Both chassis have 8 ohm mini speakers to simulate engine sounds [not very accurately I have to admit]. The chassis are interconnected with a 6-core cable.
I started investigating the details of this locomotive by e-mailing Sydney Leleux. He had taken a number of published photographs of the locomotive in about 1960, just before it was scrapped. Sydney kindly provided some copies of more pictures he had taken. He also introduced me to friends of his who had been on visits to the Kettering Furnaces site. Roger West had taken measurements of 6412 and produced a scale drawing, a copy of which he kindly sent me. Unfortunately, at the time of Roger's visit in December 1958, the loco was in the back of a shed with access only to one side and the ends.
The interiors of the model cabs had been started by Dan but were incomplete, being based on a photograph then available of the footplate of a 100HP in "Sentinel Patent Locomotives" originally published by Sentinel Waggon Works in 1931 and republished in 1974 by new owners, Rolls Royce. No pictures of the interior of 6412 were then generally available.
The model locomotive was first exhibited in November 2014, but with the subsequent publication of "Vertical Boiler Locomotives & Railmotors in Great Britain, Volume Two" by Philip J. Ashforth & Vic Bradley with the actual 6412 cab interior picture, the errors of our previous assumptions showed up. That started a new search for more detail through the good offices of the Industrial Locomotive Society. They were very helpful, providing more photographs and referred me to the Sentinel Drivers Club who hold copies of Sentinel works drawings. The amazing thing was the archivist, Richard Nixon lived in the same village as me, Aston Clinton! Richard could not have been more helpful; he perused, with me the collection of drawings held on his computer and identified those which would assist me with my project.
All I had to do now was to amend what had been built previously! It is not always easy to break up a model that took such effort to build in the first place, but that had to be done. The old boilers were stripped out and discarded and new ones built based on the drawings to hand. I was not familiar with Sentinel boiler engineering so every opportunity was taken to peer into Sentinel lorry cabs! I am sure some of the drivers, all very kind & accommodating must have thought I was mad. The only trouble was, the interior of a steam lorry cab is not easy to photograph and many of the critical fittings I wanted to see were shrouded to protect the crew!
New boilers were fabricated in plastic sheet with various cast white metal fittings, available to railway modellers altered and fitted to represent the arrangement on 6412. I would appreciate if experts in such matters do not look too closely at my efforts! The water sight gauges as purchased were too long, so I cut out the white metal parts that were supposed to represent the sight glasses and substituted clear plastic with the edges painted 'brass' for the frames. The twin regulators and single reversing lever were made of plastic and brass. The caps to the chimneys were formed of brass with working operating arms extending down the chimneys. Pipes were formed with various sections of brass & copper wire. Lagging was fine string bound around the 'pipes'.
One detail of 6412 which had puzzled me, and many others was the rodding on one side of the locomotive as seen in various photographs. All other construction details tended to be the same for each locomotive but the rodding showed on only one side of the locomotive when coupled. Many theories were advanced by others, but it was John Hutchings who first ascertained for me their correct function. Surprisingly for an industrial locomotive, the rodding operated water jets washing the rear wheels. Presumably the locomotive working into quarries got a build-up of dust on the wheels requiring removal.
All the historical photographs of 6412 are in black & white so no clue on livery. There are faint traces of the lining in some of the later pictures of the rebuilt locomotive. There are works pictures of the original locomotive as it left the works in 1926 and also in 1928. These show quite ornate lining [for an industrial loco] in 1926 but simpler lining in 1928. Fortunately when Roger did his measured survey he saw the original livery where the Sentinel plate had been removed. He told me: "The shade was very near the light green used by the then countrywide Tilling Group to paint its buses in the 1940/50's. This might be the old pre-WW2 BS 381 C standard colour 218 Grass Green". He also noted the lining - "A broadish black line edged off white both sides ... but the upper front of the cab was not lined".
The lining was the first I have ever attempted on a model. Waterslide transfers were obtained from Rail-Road to the correct pattern. The use of a North West Short Lines "Chopper" guillotine ensured the mitres were all cut to 45 degrees! It was then a case of patiently working around the model one side at a time and leaving overnight to dry before attempting the other side.
I am going to be bold and say the model is complete! If any further information comes to light that contradicts the above then ...... thank you and good night!
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1928 rebuild works picture.
Copyright: The Industrial Locomotive Society collection. |
Forlorn state just before scrapping, operating gear for wheel washers clearly visible.
Copyright: The Industrial Locomotive Society collection. |
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Interior of cab; long lever is the reverser, wheel and chain to left is regulator, links for both to other engine below footplate.
Copyright: Vic Bradley, Industrial Locomotive Society collection |
Model cab interior.
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Two views of the finished model.