Maths help needed

Eaglecliff

Eaglecliff

Registered
19 Jul 2010
1,184
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Derby, England
I am not a mathematician!
Problem: I have a photo of an ancient timber boxcar I want to model. The side of the car is divided into 9 apparently equal bays with external “X” cross braces on each end panel, and single braces going from bottom left to top right of the left hand 3 braced panels, bottom right to top left of the three right-hand panels, the centre panel being the open doorway.
The end of the vehicle and the doorway look to be in proportion as between height and width, allowing for perspective, compared with a Bachmann box van and what one would expect on a real boxcar. My difficulty arises from the fact that the “X” braces on the photo appear to be at a shallower angle to each other than my attempted full-scale drawing permits. This suggests that the model in the photo may be longer than a standard Bachmann model (remember 1950’s Hornby carriage models?) or does the model represent a longer, or lower height, vehicle? The axles look to be mounted close together in small bogies which look perhaps a bit further apart than might be expected.
Is there any way I can establish the perspective of the photo and use it to calculate the actual dimensions of the model?
 
dunnyrail

dunnyrail

DOGS, Garden Railways, Steam Trains, Jive Dancing,
25 Oct 2009
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Oh this all sounds very tricky, looking at Tac’s superb van assuming this to be a model that matches 2ft gauge on 45mm scale the model proportion is tricky. In normal 16mm models it would run on 32mm track. But running on 45mm track 22.5 mm to the foot. However is this what Tac has done. We all know about the flexible LGB rule so proportionality rules somewhat (or not really rule). Thus we play the game to match the size with whatever size in terms of height and width the loco is.

Now returning to the Eaglecliff problem, I would cut an end profile using some corrugated Cardboard from a discarded box, cut a side same height but at what looks to be a suitable length. Measure that, divide by 9 then draw lines to represent the equal bays and I reckon you would soon (maybee after a couple of efforts) get near what you want in terms of an external profile. You could then use that rough to get idea’s of the size of other parts before cutting chosen build material.
 
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David1226

David1226

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24 Oct 2009
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The problem is that 8 out of 5 people cannot do fractions

David
 
Eaglecliff

Eaglecliff

Registered
19 Jul 2010
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Derby, England
Can we see the image, please? I am a photogrammatist as part of my profession of imagery analysis and I've often used just one view to scale an measure a railroad car that I want to build. Like this one -

View attachment 261194
Much as I would love to, there is a problem, mostly it has to be said, with my technical ability. The image is from a Pinterest file which I can only get up on my iPad, not my pc, and I had to photograph and print it.
Can we see the image, please? I am a photogrammatist as part of my profession of imagery analysis and I've often used just one view to scale an measure a railroad car that I want to build. Like this one -

View attachment 261194
Thanks for your reply. The immediate answer is “No.” The image is from a Google search on my iPad which took me to a UK Pinterest site, but the same site does not come up on a search on my pc however hard I try, including using the keywords attached to the iPad pic. Without a “right-click to copy” facility on the iPad I can’t transfer the image to a place to save it so I used my DSLR to photograph it and then print it off. There is no source quoted on the original image.
Perhaps a more straightforward solution to my problem is to discover whether Bachmann simply use a standard, common, vehicle length, which I am trying to base my model on, while this particular vehicle was more than 30’ long? Say 40’ ? The prototype looks quite early (it appears to be a hopper with an unexpected middle door, rather than a boxcar - the ends slope; perhaps it was built before vehicle tippers came along and cheap labour was readily available to shovel the contents out, and the industry had not anticipated the industry’s, and Bachmann’s, desire to adopt a standard vehicle length?
In the event, I shall probably just stick to the Bachmann chassis and omit a couple of side panels...or build a 40’ chassis from scratch...
 
voodoopenguin

voodoopenguin

Retired
20 Jul 2015
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Blofield, Norfolk
Without a “right-click to copy” facility on the iPad I can’t transfer the image to a place to save it so I used my DSLR to photograph it and then print it off.
Press and hold the top or side power button and then click the Home button and release both. Screen grab will be saved and you can then forward it via email, Facebook or whatever.

Paul
 
dunnyrail

dunnyrail

DOGS, Garden Railways, Steam Trains, Jive Dancing,
25 Oct 2009
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St.Neots Cambridgeshire UK
Press and hold the top or side power button and then click the Home button and release both. Screen grab will be saved and you can then forward it via email, Facebook or whatever.

Paul
As Paul says and use Two fingers spread out on screen to get the image as large as you can. Mail it to me and I will Cad it for you then send you a .pdf with dimensions on it.
 
P

Paul M

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25 Oct 2016
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Gavin Sowry

Gavin Sowry

Garden Railroader and Raconteur
27 Oct 2009
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Hutt Valley, NZ
That just about sums it up! :)
C'mon, let's not get too divisive about this. Adding is about the limitation of some here, by admission.
 
Rhinochugger

Rhinochugger

Retired Oik
27 Oct 2009
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North West Norfolk
I might be there... Halleluja! View attachment 261204
Two things go through my mind.

Is that a representation of a converted hopper wagon?
Is it a model of a narrow gauge wagon?

While it's possible that the narrow gauge lines, or possibly one of the short lines would have converted a wagon in that manner, it doesn't appear to have the proportions of a narrow gauge wagon, and that may be the difficulty when comparing it with a Bachmann 1:22.5 wagon.