I like hundreds of other steam fanatics have longed for a steam driven engine that I could ride and enjoy the fruit of my labours.The excitement of seeing it work for its living after spending so much time and money on my beautiful creation has spurred me on through at least seven projects.However because of the limitations of my hobby styled workshop and the costs of anything larger I have devoted a great amount of time, money and energy into 2" scale models.Though I say it now , most of my projects gave me many sleepless nights and a massive learning curve, even at the age of 65 yrs I learn something new every day. Yes they have also cost me an awful lot of money during the process. It is my wish to pass on such information to my fellow e-bayers whom have the same or similar goals in life. My load of doubts, wonders and expectations have been lifted somewhat by my recent visit to the Harrogate Modellers Exhibition 2008 where I met hundreds of fellow entheuisiasts and gained a whole mine of information and expertese.
At the exhibition there were around eight or nine working traction engines of 4" scale, one 3" scale and one 2" scale models along with two other petrol powered vehicles and a full size steam car which worked passenger carrying for the whole day in front of the two exhibition halls. I as a matter of course have taken quite a few photos of the occasion. My first note of interest was that the traction engines were all coal fired, the smell of hot oil,scorched paintwork and the smoke only added to the ambience of the display. I spent around three hours chatting to the driver builders of these magnificent steam vehicles, enquiring about their problems and some of mine whilst building and running these machines.Most of the 4" scale engines appeared to be running under a steam pressure of 40 to 60 psi, the steam car (probably because of its size and weight) ran at a constant 100 psi, the 3" scale model as I saw it ran at 80psi plus whilst the little 2" scale model required a massive 120psi for anything like power to haul one adult driver and trolley. As explained to me by the builder driver of 'Auld George' 4" scale, it is relative to the surface area of the piston. i.e. the triple expansion marine engine uses every ounce of energy from the injected steam,the final piston being say 4ft in diameter required only 5psi to enforce work onto the crankshaft, there is a lot of square inches in a 4ft diameter piston?In full size marine work the first piston would be say 18" dia, the second piston would follow the rule of expansion being 2ft 6" dia whilst still observing the rule the final piston would be 4ft dia the expended steam would be then exhausted into a condenser and the reclaimed water added back to boiler to work all over again.When the rules of expansion are applied to working models then the scale size of the working piston must determine the working pressure required from the boiler. I am still thinking about that comment but I have no doubts that the many true experts out there in e-bay land will have the final answer to that. I have learned from experience that the smaller the piston then the higher the pressure required to work depending on the final effort required. The stesses and strains of working at such high pressure of steam will undoutedly make its effect felt to even the most finely engineered engine and its bearings, drive train etc. along with the inherant dangers incurred with working at these pressures. Safety Health and Welfare recommendations are limited to a working environment of a maximum 100psi, or so I am informed by others.
In conclusion and after a lengthy detailed conversation with the builder driver of the 3" scale model, the demands on a small scale engine are astronomical compared to its larger brother the 4" model. A 2" scale model although often advertised by manufacturers etc. as passenger hauling vehicles will have to work very hard indeed on perfectly level ground covered in fine tarmacadam surface to haul its driver and trolley. The strain and effort in doing so will eventually take its toll on such a small scale engine and its working life will be drastically reduced accordingly. I know that there are out there lots of pundits and owners of 60 yr to 100 year old steam engines working to this day or so the owners may claim. But at what costs in maintenance and re-builds? that is the question, along with doing what kind of working life has it had? I observed the 2" model on the day was hauling the driver and trolley but it was the most affected model there in appearance and the engine was well and truly baked along with the boiler cladding and its many ancilleries.The owner driver of the 3" model told me that he carefully selects the modelling venues that he attends i.e. a level tarmac running area is a absolute must. 'On grass the model is just a static display item' quote direct from the builder.It is not my intention to deflate your entheuisiasm for the 2" scale models but make you aware that to put your finely detailed 2" model traction engine to a working life of passenger, driver hauling will take it toll on the finish and the appearance of your pride and joy and greatly reduce its working life unless maintained to a very high standard. The obvious choice for passenger and driver hauling without any doubt at all will have to be a 4" scale model that will take its toils without to much complaint should you take the passenger hauling route to its life.
As previously stated my workshop facilities and financial situation have limited me personally to build 2" scale models only. I have built four 2" scale wagons and one 2" scale traction engine (Burrell Compound Engine 5 tonner) And I will now only run them, or try to as driver hauling engines on perfectly level tarmac areas only. Even this at only occasional intervals as they arise. During the remaining interval of their lives they shall remain as beautiful static display models to be admired and enjoyed as miniature models of their bigger brothers.Do not like myself expect to much from your creation unless it was designed specifically for the task? For comparison only a 2" model may cost anything from upwards of £2,500.00 to buy and build depending upon your intentions for the final product. A 4" model may cost you anything from £5,000.00 upwards for the parts plus costs of machining and build time £20,000 would not be unreasonable. I am afraid that the old addage of 'you only get you pays for' definitely applies to your choice of steam traction engine.
Hope that this observation , that is all the above is, of steam modelling helps with your decisions in choice of model? I am not and do not pretend to be an expert in this topic of steam driven vehicles. It is not my intention to influence readers in any direction whatsoever. But to inform the reader of my experiences in building and trying to run 2" scale models. The general opinion of those experts that I encountered on my visit to Harrogate 2008 convinced me to write my observations that may be of use to other steam entheuisiasts. If I have offended anyone including manufacturers then I can only apologise in advance for that is not my intention at all.