Finally, something different you all say.
While in Christchurch for the Trainz weekend I had the chance to catch up with some like minded modelers from Wellington. Discussions with Michael centered around steam locos and what could be done to built prototypically accurate models in the scale. The next week I received in my inbox a document where he had broken the various loco classes down into their respective wheel size and wheelbase dimensions. His hypothesis is that its possible to make almost all the steam locos that ran in this country using 4 basic frames and 5 different sized wheels. He's also completely correct.
This meshes in very nicely with my thoughts on the subject (which have been discussed in the back blocks of this blog I think in 2008). As Michael has pointed out in his document (which possibly should be put up on the NZ120 site) it is possible to create an 'end of steam' motive power list that with just 2 frames (10' 6 coupled and 14' 8 coupled)and 2 wheel sizes (45" and 54"). Now, my plan with the K/J frame is to extend the axle spacing out to 5' vs 4'9" and make the wheels smaller at 11mm vs the 11.43 that they should be. This is so that an NMRA standard tire with a 0.5mm flange can fit, and still have a 0.5mm gap between the wheels. Now, for the smaller diameter wheels I'm seriously considering having one size to do both the 49.5" and 45" as the diameter difference is only 0.8mm and if we pick 47" as an intermediate it gives us very close to 10mm. in either case the different counterweights can be added as etched shapes later.
While in Christchurch for the Trainz weekend I had the chance to catch up with some like minded modelers from Wellington. Discussions with Michael centered around steam locos and what could be done to built prototypically accurate models in the scale. The next week I received in my inbox a document where he had broken the various loco classes down into their respective wheel size and wheelbase dimensions. His hypothesis is that its possible to make almost all the steam locos that ran in this country using 4 basic frames and 5 different sized wheels. He's also completely correct.
This meshes in very nicely with my thoughts on the subject (which have been discussed in the back blocks of this blog I think in 2008). As Michael has pointed out in his document (which possibly should be put up on the NZ120 site) it is possible to create an 'end of steam' motive power list that with just 2 frames (10' 6 coupled and 14' 8 coupled)and 2 wheel sizes (45" and 54"). Now, my plan with the K/J frame is to extend the axle spacing out to 5' vs 4'9" and make the wheels smaller at 11mm vs the 11.43 that they should be. This is so that an NMRA standard tire with a 0.5mm flange can fit, and still have a 0.5mm gap between the wheels. Now, for the smaller diameter wheels I'm seriously considering having one size to do both the 49.5" and 45" as the diameter difference is only 0.8mm and if we pick 47" as an intermediate it gives us very close to 10mm. in either case the different counterweights can be added as etched shapes later.
So, why would this make sense? For one thing, it will simplify the work required to get wheels mounted square on axles by minimizing the number of jigs. There is only one etch requires for the frames and coupling rods for both versions.
OK, so what does the peanut galley think. Would my simplifications result in you all to be less likely to buy a loco kit if the mechanism/wheels are not quite the correct size in order to improve the overall running quality?
I suppose you would all want pre assembled mechs anyway....
(Cheers to Mike for the inspiration for this post, hopefully I can run with it a bit further)
OK, so what does the peanut galley think. Would my simplifications result in you all to be less likely to buy a loco kit if the mechanism/wheels are not quite the correct size in order to improve the overall running quality?
I suppose you would all want pre assembled mechs anyway....
(Cheers to Mike for the inspiration for this post, hopefully I can run with it a bit further)
6 comments:
I guess it comes down to how motivated by rivet counting we are- or not. I have been lurking around NZ120 for about 18 months and the attraction for me is as others seem to push- the "big" picture. Realistically if a NZ120 Ab was sitting beside a NZ120 K I don't think I would really notice if the driving wheels were the same size (even though they aren't in prototype). Most NZ120 modelling up until late was pretty rough and ready and making do with what you had (I hope I haven't offended anyone as that is not my intetion). Its the old 2 metre rule- I wouldn't be pawing over a nz120 model with a magnifying glass tut-tutting on ther fact that 3 rivets were missing from the tender! I was impressed with the picture in the Journal(?) recently of the Ab John Rappard built utilising a chassis from a Japanese steam engine and if anything the cherry blossom driving wheels just added to the model and what had been achived in it's construction. For ease of construction I say go for the similar sized drivers between the two different frames- it makes sense from a ease of manufacture point of view. (Rant over!!!)
(which possibly should be put up on the NZ120 site)
that would defenitely be a good idea - these kettles are slowly growing on me and sooner or later I have to try to build one for me as well (that would be project # - I have no idea, I lost count...)
steve w.
'talin'
One of the things that we are trying to move forward from is the 'making do with what we can get' attitude of the past. We are seeing that in Darryls x bogie sideframes, and my ham fisted attempts to make track.
(oh and the Ab and the K series shared the same sized wheels, with the same number of spokes)
Fair enough- and I am amazed at the evolution of the scale over such a short period of time (and particularly the history piece the Journal has made into a bit of a strip tease!!). Thanks for picking up the fo-par on the Ab/K wheel sizes I knew the J and K classes shared wheel size but was unsure on the A/Ab's with the J/K classes (guess I should have googled it....!). I think what I was trying to get at was that this scale shows more than its fair share of ingenuity with what you guys are achieving and have achieved. The kit bashing aspect of the earlier days of NZ120 is a large interest for me in the scale.
I'm cooking up ideas of a certain line between Wgtn and Longburn in the late 1890's that will involve a lot of kit bashing- I'll leave Paekak' to you though! Keep up with good work with the blog!
The early pictures of Paekakariki in company days show that its actually a more resonable modeling prject as the loco depot is far closer to the station.
However a far more interesting model would be the climb out of wellington up to Johnsonville. This could make a very spectacular home layout.
A "thunderingly good idea" mon - only trouble for me is your continuing fascination with those steam beasties of the larger inclination.
A number of UK etch loco suppliers already produce various "chassis kits" for N scale UK & 2MM UK style sream locos of the smaller variety.
By way of example "http://www.nbrasslocos.co.uk " produce correct profile frames(with ashpan & axlebox detail, coupling rods, brakes & linkages for a 2-4-2 chassis (axle spacing 13.5/15/5/13.5mm) & an 0-6-0 chassis with axle spacing at either 15 or 16mm - they also do a tender chassis 6 wheel, with 12/12 or 12/13mmm axle spacing, so only good for Canty J.
In addition to them, I know Worsley Works provides some vari-chasses & I believe Bill Bedford can produce several types of frames in 2mm scale.(all split frame design compatible).
I also think there are some frames available from the 2mm Soc to members - not sure which ones tho.
So an opportunity to do some further sleuthing to see what fits what in TTn3.5 - if there was enough demand, there is a UK outfit which can custom mill chasses as well - not sure what the cost would be, but you "big engine" guys could check them out - they advertise in the UK MRJ.
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