Scale & Proportion on 7.25 track

 
  philbert metaSHAFT Developer

Location: In the conservatory, with a candlestick
What's the deal with this whole 1/5 scale on 7.25" track thing?  The locos always end up massively overpowered, very crude looking (little or no detail), and out of proportion (oversized hoods, elongated cabs, etc.)

If someone wanted a big loco, why not build a 3'6" protoype on 7.25" track, thus giving a scale of just under 2"/foot.  An AN/ARG 830/DA class loco built to such a scale would come out at over 2.5 metres long.  Having said that, an SRA 90 or PN NR class loco built at 1.5"/foot ('standard' gauge for 7.25") would come out at 2.75m long - that's pretty bloody big!

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  dthead Site Admin

Location: Melbourne, Australia
What's the deal with this whole 1/5 scale on 7.25" track thing?  The locos always end up massively overpowered, very crude looking (little or no detail), and out of proportion (oversized hoods, elongated cabs, etc.)

If someone wanted a big loco, why not build a 3'6" protoype on 7.25" track, thus giving a scale of just under 2"/foot.  An AN/ARG 830/DA class loco built to such a scale would come out at over 2.5 metres long.  Having said that, an SRA 90 or PN NR class loco built at 1.5"/foot ('standard' gauge for 7.25") would come out at 2.75m long - that's pretty bloody big!
"philbert"


First of all it comes down to personal preference, but there are other factors. Fisrt of all there are many locos that look the part and are scaled as much as possible. I agree there are bad examples out there as well, and that applies to locos at any scale. There iare good and bad examples in any size. What a person want to build is up to them - logic doesn't usually enter into the equation. Skill, time, personnal motivation all contribute to the final product.

Then there is the power thing that relies of physics to a degree- A Steam loco can be scaled down - a steam loco is a steam loco whether LGB size, 5inch,  15 inches, 2ft or 5ft 3 inches.  Petrol or Diesal engines are not so easy to make. You usually have to find a 'real" engine and fit it in. Then if you are usiong electric traction you have to have a generator/motor combination that works and move your loco with enoght power to satisfy you.

You can get down to 16.5 inches between the inside frame by using a Mazda 323 ( 1983-1986 era) engine. Obviously since one would be building in scale it will not fit in may a loco if scaled to 3ft 6inches.

"an SRA 90 or PN NR class loco built at 1.5"/foot ('standard' gauge for 7.25") would come out at 2.75m long" - but wouldn't fit a engine in it easily. Would look nice if done well.

That bring me to power - if all you are doing is pulling 1-3 people you could look into smaller motors ot batteries - many people do that. Or you can try a smaller 2 stroke engine  ( ie lawn mower etc.) - but they do sound terrible if you want the sound of a bigger loco as well. Now lets look a tthe "big" engine - yes they want power to pull

DVR for example has some long grades, and we are pulling 2 tonne of train&passengers. You do need the power for that ! When DVR engine go elsewhere yes they are idling around alot of the time - just like the real thing does when they  also move around "light engine".

I hope these examples show why  a Big loco may be just as good as a "scale" loco, and why they are what they are.

A very nice post to reply to !!!! But I may split it form this discussion as it does not relate to the topic it is in....
  philbert metaSHAFT Developer

Location: In the conservatory, with a candlestick
Point taken about detail and accuracy, and I have seen some very rough and ready steamers.  Based on my experince though, it seems more prevailent amongst the petrol/electric community - perhaps because of the general rule that a petrol/electric is the quickest way to get a loco up and running (no boilers, etc., to worry about, and far more off the shelf components).

However, I think the power argument is a bit exagerated.  A large 5" steamer (garretts, etc) can pull 2,000+Kg trains up grades, and they might pump out 5Hp.  To go from that to a car engine that puts out 50+Hp seems a tad excessive.  Apart from anything else, it would completely remove any element of skill on the part of the driver.

I guess it gets down to, are you doing this for interest in a hobby, or to turn a profit.  (Classic difference between DVR and the rest of the AALS, IMHO).
  dthead Site Admin

Location: Melbourne, Australia
Point taken about detail and accuracy, and I have seen some very rough and ready steamers.  Based on my experince though, it seems more prevailent amongst the petrol/electric community - perhaps because of the general rule that a petrol/electric is the quickest way to get a loco up and running (no boilers, etc., to worry about, and far more off the shelf components).

However, I think the power argument is a bit exagerated.  A large 5" steamer (garretts, etc) can pull 2,000+Kg trains up grades, and they might pump out 5Hp.  To go from that to a car engine that puts out 50+Hp seems a tad excessive.  Apart from anything else, it would completely remove any element of skill on the part of the driver.

I guess it gets down to, are you doing this for interest in a hobby, or to turn a profit.  (Classic difference between DVR and the rest of the AALS, IMHO).
"philbert"


We do it for fun, just as every other AALS club.

Yes I have ssen my share of "odd" locos in my time. What a diversity though !

Since I know a person who has built two locos that you may not like, though they are a very good representation( i've seen worst HO scale models), I can tell you for him, it is for fun. He is likely to build a 5 inch loco sooner or later for the same reason, to take aorund.

If there was a ultimate loco scale guage combo, I think there would be little interest. To each their own I say. I like all the sizes, and do not judge a guy's efforts based on my likes or dislikes.  

As for a scale diesal engine, the engineering skills are beyond most people who want to build a loco, think of all the work !  You cannnotsc ale nature ( that is why your example of a garrett works - the pressure is real world. Making a diesal in scale hard, and has been done, but not withing the skill of most people. Even if there was a scale diesal, the genertor it could turn to provide enough power would be impossible, as for the motors to move the loco a equally difficlut challange. Motors that small and being that powerful are either so expensive or nonexistant.

I would love to see a scratch built Diesal-electric loco - it would be a great achievment to see. But would be able to pull people aroung a heavily graded line like we enjoy doing( the answer is  it doesn't matter, the loco only has to perform for the owner to his/her espectations).

The hobby cannot exclude everyone who cannot operate a full workshop with all the tools and skills. When I see a "eyesore", I do not worry about it, I go for the loco I want to see or drive. I enjoy all sizes etc. and I know I am not alone in liking the hobby as a whole.

As for the driving experiance - well they are great. The electric traction is the least used method - most seem to go for mechanical or hrydraulic.
The electric loco perform close to the real thing - I know with former (yes I am refering to a departed friend) and current loco drivers in our club that the electriv loco performs closeer to the real thing. You have to power up gradually, look after your motoros depending on the load you have, braking is equally interesting as you roll down a hill as you apply your brakes to  make sure the train's speed does not get away from you.

Diesal Hrydraulics can also be complex to drive, but I prefer the electric traction. I have found with  a loco with a closed hrydraulic drive they are like a model train, dial up the forward direction you go forward, return to neutral the train stops. dial reverse etc. Boring !!! But for someone else that may be magic for them !

Once again a good debate. No one will win an agrument - and I know all I'm doing is chatting on the topic. I know I am not right, but  I am not wrong either.

These are my opinions as a member of DVR, and a visitor of many other miniature railways.

Regards,
David Head
  X-Trapolis(Melb Rocks) Train Controller

Location: Melbourne
so what is the scale for 7 1/4 inch 1 to what?
Tim
  d1565 Deputy Commissioner

Location: Perth
Scale depends entirely on your prototype, then there's a little thing called 'modellers license' to cosider (ie it's my loco , i can build it how i like) in regards to the copment about building a 3'6" guage loco at 2" tho the foot scale, bear in mind a Westrail S class is 22 metres long over couplers, ditto for the QR 4000 and 2800 class units. these loco's when scaled out to 1/6th scale (2" to the foot) come out around 3.6 metres long, so in no way are these any differant to the other loco's i think you are probly referring to (DVR maybe?) the other point to consider is that of being able to ride in the loco, not on a riding truck behind. by riding on the loco itself, you have better visibility, control equipment is easier to set up as it doesn't have to bend with the curves of te track, and by the time you add the size of the riding truck, you may aswell have just buiilt the loco to a bigger scale....

Just a few thoughts......
  philbert metaSHAFT Developer

Location: In the conservatory, with a candlestick
I agree totally with the benefits of large locos.  At my club we have a 5" gauge NA (2" scale) which is, for 5" gauge, a very large loco.  I've seen a D&RGW K-36 (or was it a K-28?) steam loco on 7.25" gauge (~2.5" scale), and it was a huge loco.  I have considered building a gauge convertable 830 class (1.5" scale) for operation on 5" and 7.25" tracks.  At about six feet long, it would be quite a large loco too.

The difference is, all these locos are (or would be) accurate representations of prototypes.  Having said this, I don't have a problem with freelance locos either - that allows the builder complete freedom.  The thing that I don't understand is why, given all the prototype possibilities, someone would want to build a model of a real loco at the wrong scale for a given gauge.  There's a G class that springs to mind (I believe its at Box Hill in Victoria) the exemplifies this approach...
  philbert metaSHAFT Developer

Location: In the conservatory, with a candlestick
so what is the scale for 7 1/4 inch 1 to what?
"X-Trapolis(Melb Rocks)"

A standard gauge loco built for 7.25" track is generally built at 1.5" to the foot (or 1/8 full size).  As the prototype gauge decreases, the scale increases, because the model gauge (7.25") is fixed.

4'8.5" => ~1.5" scale
3'6" => ~2" scale
2' => ~3.6" scale

etc..
  dthead Site Admin

Location: Melbourne, Australia
I agree totally with the benefits of large locos.  At my club we have a 5" gauge NA (2" scale) which is, for 5" gauge, a very large loco.  I've seen a D&RGW K-36 (or was it a K-28?) steam loco on 7.25" gauge (~2.5" scale), and it was a huge loco.  I have considered building a gauge convertable 830 class (1.5" scale) for operation on 5" and 7.25" tracks.  At about six feet long, it would be quite a large loco too.

The difference is, all these locos are (or would be) accurate representations of prototypes.  Having said this, I don't have a problem with freelance locos either - that allows the builder complete freedom.  The thing that I don't understand is why, given all the prototype possibilities, someone would want to build a model of a real loco at the wrong scale for a given gauge.  There's a G class that springs to mind (I believe its at Box Hill in Victoria) the exemplifies this approach...
"philbert"


I know what you are saying (well my thoughts on what you are saying )
is you prefer a scale loco to match the gauge rather than incrrect scale/gauge combination.

The Box hill "G" is a example(but wouldn't pull a 6 car train at DVR fully loaded up our grades), yes, but  there are many locos that come in
as good representation of their prototypes. S301 at DVR has good detail, it is all in proportion, there is a fully modelled cab. The only two main things 'wrong' is the gauge it runs on and the space in the roof for the driver.  And there a re a few other locos at DVr that match this as well.

It doesn't worry the owners of these locos that the wheels are slightly narrower - their bogie sideframes are correct. So looking at the loco side on it look correct.

Again it's up to the builder. This scale gauge choice happens in many a scla gauge combo - look at how the British used 4mm /ft sacle with 16.5 mm track - or many a VR or SA ho scale modeller who happlily drives his D3 or RX class stema loco on the same track as  a 38 or NR loco.

Remember for the power and ride you have to go so big. Having said that it is up to you what you build. I'll agree a proportioned scale/gauge loco can loo fantastic, but I wouldn't label a loco bad just because they may have compromised that ratio.

Remember someone will swear by the NA as THE model to build and will not understand why everyone else builds other type of locos. I'm not going to convince him/her, and they will not convince me.  I prefer not to judge people's efforts - and enjoy the for what they are, big small, a box on wheels, a boiler on a frame, whatever.


Regards,
David Head

ps you do understand I'm talking friendly here and in no way are offended by the views othere have, nor as I said trying to convince you to my way of thinking. I just hope you are equally enjoying the conversation.
  X-Trapolis(Melb Rocks) Train Controller

Location: Melbourne
thanks guys for that information
Tim

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