Locomotive scales

[Chris HammondParticipant @chrishammond37041]

Hello all

I am new to this fantastic hobby, so please forgive my banal questions which you have probably heard 100s of times already!

I am getting myself confused with locomotive scales. I am considering building my first locomotive, based on my long held passion for American steam and Baldwin-type locomotives. I want to build something like the Lucky 7 from Reeves.

Obviously, a great place to research these locos 's on American sites, and of course, they like to build them big. I love big loco's but have been told that my Chester Cobra mill will struggle to cope with the machining required on something in 7 1/2 (or 7 1/4) scale. For e.g., one of the loco frame rails would need to be milled from 16mm mild steel. A Bridgeport mill is out of my budget unfortunately.

Anyway, I am thinking around the 3 1/2" scale. I haven't yet researched a local club where I could run it (perhaps I should be fore deciding) but am not yet 100% sure I actually want to run it regularly. For me the thrill lies more with the actual building. And I guess, polishing!

So, I checked out the Reeves site which lists the Lucky 7 loco in 3 1/2" scale. Then confusingly (to me) it says it is also available in 7 1/4 and 7 1/2 as MINI Lucky 7, which implies the 3 1/2 scale is bigger? What am I missing.

Could you gentlemen give me some steer please on the pro's and cons of different scales (obviously a huge consideration wth the bigger scales is the physical weight of the loco). I would be very grateful for your musings and thoughts.

Chris

[Chris HammondParticipant @chrishammond37041]

[NJHParticipant @njh]

Hi Chris

The 3 1/2", 5", 71/4" are not SCALES but the gauge of the track ( distance apart of the rails). Sure a loco built for 3 1/2 gauge will be smaller than the same design built for 5" gauge.

So your first consideration is where will you RUN your loco when it is completed? If your local club has no 3 1/2' gauge track then designs for that gauge would not be a good idea!

I would suggest that you seek out your local club and go along, talk to the members, look at the operation and locos in the different gauges, and see what takes your fancy. Think long and hard as building a loco is a long and fairly expensive venture!

Good Luck!

Norman

[Chris HammondParticipant @chrishammond37041]

Hi Norman

Right, ok I see where I have got confused.

Thanks for your reply.

Chris

[Roderick JenkinsParticipant @roderickjenkins93242]

Chris,

I think it's Reeves, not you, who are confused. When you look at Reeves 7 1/4 locos it's called the Maxi Lucky 7. "Mini" just a typo I think.

Rod

Edited for my typos 

Edited By Roderick Jenkins on 04/01/2017 12:43:49

[Chris HammondParticipant @chrishammond37041]

Rod, thanks. I might not be the brightest coal in the bunker but I kept looking at it and thinking… 'what am I missing'?!

Anyone any advice please on whether the mill I have would cope with the bigger loco's parts?

Chris

[JasonBModerator @jasonb]

It would do it, just a lot more slowly than a larger machine as you won't be able to remove metal as quickly. The other large items to think about are things like cylinders, radius on chimney base etc where you may run out of physical capacity rather than enough grunt to do the work.

J

[Chris HammondParticipant @chrishammond37041]

Brilliant. Thanks JasonB

 

 

Edited By Chris Hammond on 04/01/2017 13:12:03

[BazyleParticipant @bazyle]

You might want to get the frames laser cut which is popular now. It can even be cheaper as they buy the material in bulk.
Also you might join the 7 1/4 association as they might have a group buy that could help, and also put you in touch with nearby private tracks and other builders. But generally clubs even if it is 30 miles each way are well worth attending as there will be advice, tools and machines for sale too Lots of people belong to multiple clubs if in the right place.

The Mini prefix might be a bit of humour by the designer or Reeves.

In the UK there are 7 1/4 and 5 in gauges but in the USA depending on location beware there are also regional anomalies of 7 1/2 and 4 3/4 I think.

[Chris HammondParticipant @chrishammond37041]

Thanks Bazyle.

Do you have contact details for the 7 1/4 association, please?

[Brian OldfordParticipant @brianoldford70365]

Another consideration should be, how will you transport and man-handle the locomotive when it is complete. Think through the logistics of moving it from your (presumably) home store to your vehicle (or trailer) and the onto the track at your chosen venue.

Those factors can have a big influence over the decision to go 3 1/2" gauge (3/4" per foot scale), 5" gauge (1 1/16" per foot scale) or 7 1/4" gauge (1 1/2" per foot scale). Those scale gauge relationships assume you are modelling a standard gauge prototype and not Narrow Gauge.

[Chris HammondParticipant @chrishammond37041]

Bazyle… don't worry. I have found them on google.

[Chris HammondParticipant @chrishammond37041]

Thanks Brian. These factors are of course very important.

Am I right in my assumption that G scale is 32mm gauge, twice the size of 16mm gauge?

 

Edited By Chris Hammond on 04/01/2017 15:34:30

[Roderick JenkinsParticipant @roderickjenkins93242]

Yikes! Even in 3 1/2" gauge Lucky 7 has a 6" diameter boiler, the original seems to be 2ft gauge. The 7 1/4 " gauge version would be enormous and (probably literally) weigh a ton.

Cheers,

Rod

[Another JohnSParticipant @anotherjohns]

As Rod says, the 3-1/2" gauge Lucky 7 is for a two foot prototype, so it is 1/8th scale, and weighs in some where around 300 pounds. The wheels are inside the frames. The original (plus others) exist, (mainly?) in the state of Maine.

One can also put the wheels outside the frames, and build it for the same 1/8th scale, but 7-1/4" track. Don Young, when writing it up for the American Live Steam magazine, specified this as an option. Then someone (don't remember who) doubled up the 3-1/2" gauge version, for something like 1/4 scale on 7-1/4 track.

If you take the figure of 300 lbs as "correct" for the 3-1/2" gauge version, and you make it 2x longer, 2x wider, 2x higher, you come to 300 x 2 x 2 x 2, or 2,400 lbs, so Rod is (as usual!) quite right on the mark.

At one time I thought that the Lucky 7 would be on my "build" list, but it really is quite a heavy locomotive for elevated 3-1/2" gauge track.

Regards, John.

[Chris HammondParticipant @chrishammond37041]

Actually no, I have that wrong! G gauge is smaller than 16mm gauge according to my book by Peter Jones.

You then have 7/8 gauge – which is a lot bigger!

Jeepers, this is crazy confusing…. I literally cannot get my head around it.

I think I'll go back to building planes!!!. 1/4 scale 1/5th scale, 1/6th scale…. aaahhh so simple. So easy to understand.

[Russell EberhardtParticipant @russelleberhardt48058]

In the days when that model was designed most model engineers didn't have milling machines. Perhaps what is more important is what the capacity of your lathe is. You can always cut the frames by hand!

Russell.

[Boiler BriParticipant @boilerbri]

So how long is a 5” scale mile?

Bri

[BazyleParticipant @bazyle]

6 & 2/3 chains of course

[Boiler BriParticipant @boilerbri]

I take that as a joke seeing its April. Looking in google a chain is an old fashioned measurement.

Seriously though what is the answer.

[michael howarth 1Participant @michaelhowarth1]

Posted by Chris Hammond on 04/01/2017 16:07:01:

Actually no, I have that wrong! G gauge is smaller than 16mm gauge according to my book by Peter Jones.

 

I think that you may have misread something Chris. Garden (G) Scale is usually 16mm (to the foot). The track on which it runs may be either 32mm (gauge) or 45mm (gauge). "Scale" and "Gauge" are not interchangeable terms.

I usually build Gauge 1 stuff which can be either 10mm to the foot scale or 1/32 scale. Either will normally be built to run on 45mm gauge track.

It follows that Gauge 1 locos @ 10mm scale will also run on the same track as Garden scale 16mm locos.

I hope that this has not muddied the waters further.

Mick

Edited By mick H on 02/04/2018 08:23:10

[JasonBModerator @jasonb]

About 156yds

[BazyleParticipant @bazyle]

If you think about it 5in track width is 1/12 the size of the full size track if you aren't nit picking about a few mm. So you have an easy way to scale everything at 1in = 1ft. You can instantly realise how big a 'model' train driver would be, what size your 1/4in model rivet would turn out if full size etc. 1Km of full size track then just reduces to 1/12 Km or 83m (plus a foot).
From this you can work out if your not hopeless at mental arithmetic what the equivalent is for 7 1/4 or 3 1/2 inch track. But then you find the scale in inches to the foot is not a nice round figure in fractions. You will find some designs are adjusted to make it fit a nice value and some are 'pure scale' to 10 decimal places.

All model railway track gauges attempt to go up in a sequence of root 2 times the one below but are then adjusted to fit a round figure of scale, ratio, or gauge.

Edited By Bazyle on 02/04/2018 10:42:46

[John OlsenParticipant @johnolsen79199]

If you happen to live in New Zealand, South Africa, and some parts of Australia where 3ft 6 inch gauge is used, 3.5 inch gauge is similarly convenient at 1 inch to the foot, plus you tend to get a loco that is a bit gruntiier than a standard gauge prototype would be. Similarly 7.25 inch gauge is close enough to 2 inches to the foot, and gauge 1 would be 1/24th scale

John

[HopperParticipant @hopper]

Posted by Bazyle on 02/04/2018 10:41:23:

… reduces to 1/12 Km or 83m (plus a foot).

So that'd be a metric foot then?

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