How long/big is an HO-scale diesel engine?


Spiral Storm

Spiral Storm

Member
Hi everybody!

I know I've been gone for quite some time-Very busy my life is. But what I'd like to know is this-How many inches long and wide is a typical HO-scale diesel engine? I ask because I am STILL trying to figure out how much bigger or smaller my Power Trains are in comparison to HO-scale. Thanks in advance for your answers! Cheers!
 
Power Trains, a solution for a problem that doesen't exist? I received my first Athearn Hi-Fi (rubber band) drive train set at five years of age in 1955. No problem aside from losing the occasional joiner. In a year I had more track and a couple of switches. I made tunnels out of oatmeal boxes and blocks. I loved American Flyer "S" as well and they shared space on my bedroom 4x8.
 
HO scale is 1/87th actual size, so determining the dimensions in N-scale requires only grade school math.

  1. Look up the dimensions (in feet) of a prototype engine or car
  2. Divide by 87 (to get the HO size in feet)
  3. Multiply by 12 (to get the HO size in inches).

Examples (to the nearest 0.1 inches):

A Dash 8-40CW loco is roughly 71 feet long and 10 feet wide.

71/87 x 12 = 9.8 inches long
10/87 x 12 = 1.4 inches wide


A GP7 loco is roughly 56 feet long and 10 feet wide.
56/87 x 12 = 7.7 inches long
10/87 x 12 = 1.4 inches wide


A 40-foot boxcar is roughly 40 feet long and 9.5 feet wide.

40/87 x 12 = 5.5 inches long
9.5/87 x 12 = 1.3 inches wide

Easy enough?

- Jeff
 
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Hey, Jeff! Thanks for clarifying this for me! I had no idea it was this easy to determine the size of an HO-scale engine. I thought ALL HO-scale engines and cars were the same length and width. I guess this is not really the case. I took a measurement of the only train engine I have and it is roughly 1 inch and 2 millimeters wide by 5 inches long, not including the couplers. Did I measure my diesel engine correctly? Or was I supposed to include measurements of the couplers? If the latter is the case, then my engine is actually a little less than 6 inches long.
 
Whoa! I just measured the inside rails of one section of my Power Trains track and it is VERY close to HO-scale-Exactly 15 mm in between the inside of the rails! Amazing! Since this is the case, then I can say with almost 100% certainty I can use HO-scale buildings, terrain, and the like, with my train set!

Keeping this in mind, what scale size ratio would you folks determine Power Trains to be? 1:90? 1:95 maybe? Feel free to share your thoughts!
 
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Common sense should tell you that all HO cars could not possibly be the same length. A 86-foot passenger car is more than twice as long as a 40-foot boxcar. So how could they ever be the same length when scaled down to HO?

The length of a model in any scale -- HO, N, O, etc. -- corresponds to the length of the full-size item. The term "scale," as in HO Scale, means that the size of a model is always the same fraction of the size of the full-size item. In the case of HO, the fraction is 1/87.

So, just as real locomotives are different lengths, scale models of locomotives are also different lengths. Just from your measurements, there is no way to know for sure whether or not your 5-inch engine is HO scale or some other scale. It depends on which full-size engine your model represents.

In HO scale, 5 inches is equal to 36.25 feet (5 x 87 / 12). Most real engines are longer than that, but if your model represents some sort of small switcher, it could possibly be HO scale. We can't know for sure until you tell us exactly what type of engine it is.

More common sense: To ensure that real engines and cars can travel on any railroad, the spacing between the rails has been standardized for many years to 4 feet 8 1/2 inches in the United States and many other parts of the world. And because track width is standardized, the width of cars became more or less standardized, too. As a result, engines and cars are about 10 feet wide, give or take a few inches. By standardizing the width of engines and cars, structures such as passenger platforms, freight platforms, and engine service facilities can be standardized as well. So regardless of the length of an engine or car, its width will be about 10 feet.

A final point of advice: Don't mix English and metric systems when you measure something. That's confusing. Either measure in inches and fractions of inches or measure in millimeters, but never mix the two.

- Jeff
 
I did a little searching on the web and found a discussion where someone figured out the Power Trains passenger cars are approximately the same size as TT-scale, which is 1:120.

You can't judge the scale by measuring the track width because "toy" type model trains such as Power Trains do not make any effort to maintain a consistent scale between their various components. Power Trains are models, but they are not scale models.

The Power Trains track width was no doubt selected mainly to help the trains stay on the tracks at the high speeds most kids like to run their trains and not because they were trying to match a specific scale. In other words, the track width is one ratio, the cars are a different ratio, and the engines are a third ratio. Just by looking at pictures of Power Trains, you can see that the engines are about the same length as the cabooses, when the engines would be considerably longer than the cabooses if they were the same scale.

None of this prevents you from using HO structures along with Power Trains. You should do whatever makes you happy. Just understand that matching the scales can't really happen because the Power Trains components themselves -- engines, cars, and track -- are each a different ratio.

- Jeff
 
@ jdetray I don't think I was measuring my trains correctly. I was miscounting in terms of inches and ended up skipping one inch-My engine is actually 6 inches long and my tank car is 5 inches long. Measuring in between the rails of my track again, I see it is exactly half-way between 3/4 of an inch and 7/8 of an inch. My train says TWX, however, I am pretty sure TWX is a fictional diesel engine company. The tank car has the lettering CM on it and right next to it, says 'Cryogenic Management' Systems. Based on these figures, what can you tell me about my track gauge and engines?
 
We posted at about the same time, but see my post #9 above. Your Power Trains are somewhere between HO (1:87) and N-scale (1:160). But your engines, cars, and track are all different ratios. Your track width is about a 1:69 ratio, so it's actually wider than HO scale. However, your engines and cars are smaller than HO scale. Furthermore, from looking at photos, it appears that the engines and cars are probably different ratios as well.

As you can see, there is no single answer. Your engines, cars, and track are all different ratios, some larger than HO, some smaller than HO.

- Jeff
 
Yeah, this is what I was told by Power Trains reps over the phone, however, I am not sure if I am even measuring my track properly. Do I measure the width in between the outer-most rails? Or do I measure the width from a different position? I find it hard to believe the gauge of my track is wider than HO but my trains are slightly smaller than HO-scale. So, to be safe, I measured the width of the track in the narrow space in between the two sections immediately in between the actual rails of my track section-I found it was exactly half an inch wide.

So either my track is a little wider than HO scale as you mentioned or it's a little more narrow than HO-scale. What I would like to find out is if you or anyone on these forums or anyone you know might be able to send me one section of HO-scale track and an HO-scale engine and/or car you're no longer using in the mail.
 
Track gauge is measured like this:

TrackGauge.jpg

Bruce
 
As Bruce points out, the track gauge is measured from the inside edges of the rails.

If your track gauge as measured above is exactly 1/2-inch, that's a ratio of 1:117. That is much too small for HO and is pretty close to TT-scale which is 1:120.

From your measurements of your engine and cars, they are also smaller than HO and perhaps close to TT-scale as well. So I would say that TT-scale buildings -- if you can find them -- would be about the right size to match your Power Trains.

My recommendation: If you like the Power Trains, set up a layout and watch the trains go round and round. That's a perfectly acceptable way to have fun! No one should criticize you for doing that. You can even get the crane set and load and unload some cars. If you can find some TT-scale buildings, so much the better.

The harsh reality is that the Power Trains engines, cars, and track are not realistic in either appearance or operation compared to the products offered in the established model railroad scales. Power Trains has not even attempted to create accurate scale models, but has instead made what I would call extremely rough approximations of generic railroad equipment.

Just from looking at photos on the Power Trains web site, it appears to me that the engines and the cars are out of proportion with one another. Either the cars are too long or the engines are too short -- not sure which.

The only thing that having an actual HO engine, car, or piece of track would do for you would be to show you how much more realistic it is compared to any of the Power Trains products. You can also do that by taking your Power Trains engine into a local hobby shop and comparing it to the HO products on display.

- Jeff
 
Looking at that engine you have on the PT web site, it looks like they copied several aspects of different engines to come up with the one they made. With that, I would have to say, for comparison sake, that it very loosely represents an EMD products model GP40 engine...very loosely. With that the general specs for a GP40 are...

Length over coupler pulling faces 59'2" (HO scale 8.15")
Height from top of rails (track) to roof 15'2.5" (HO scale 2.09")
Width 10'2.5" (HO scale 1.4")

If this were to be an actual HO scale model of said engine, the measurements should be what I just posted.
However, That engine does not really have a prototype that it was scaled from so to try to determine a scale for it will be almost impossible. This is similar to trying to scale out Hotwheels/Matchbox cars. Both make all sorts of different vehicles that scale out all over the place. I remember as a kid having a matchbox kenworth truck and a matchbox sports car and they were almost the same length. t was years later when I discovered that they never really scaled anything, instead made the product to fit the packaging. Your best solution with the trains you have is not to worry too much about scale and just enjoy what ever you use with them for buildings, scenery etc.
 
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jdetray said:
As Bruce points out, the track gauge is measured from the inside edges of the rails.

If your track gauge as measured above is exactly 1/2-inch, that's a ratio of 1:117. That is much too small for HO and is pretty close to TT-scale which is 1:120.

From your measurements of your engine and cars, they are also smaller than HO and perhaps close to TT-scale as well. So I would say that TT-scale buildings -- if you can find them -- would be about the right size to match your Power Trains.

My recommendation: If you like the Power Trains, set up a layout and watch the trains go round and round. That's a perfectly acceptable way to have fun! No one should criticize you for doing that. You can even get the crane set and load and unload some cars. If you can find some TT-scale buildings, so much the better. - Okay...Since you are suggesting TT-scale buildings, my next question is this-Are there any web sites or hobby shops you know of which will sell ready-made or easy-assembly TT-scale buildings? If so, how much will they cost?

The harsh reality is that the Power Trains engines, cars, and track are not realistic in either appearance or operation compared to the products offered in the established model railroad scales. Power Trains has not even attempted to create accurate scale models, but has instead made what I would call extremely rough approximations of generic railroad equipment.

Just from looking at photos on the Power Trains web site, it appears to me that the engines and the cars are out of proportion with one another. Either the cars are too long or the engines are too short -- not sure which.

The only thing that having an actual HO engine, car, or piece of track would do for you would be to show you how much more realistic it is compared to any of the Power Trains products. You can also do that by taking your Power Trains engine into a local hobby shop and comparing it to the HO products on display.

- Jeff
Click to expand...

danpik said:
Looking at that engine you have on the PT web site, it looks like they copied several aspects of different engines to come up with the one they made. With that, I would have to say, for comparison sake, that it very loosely represents an EMD products model GP40 engine...very loosely. With that the general specs for a GP40 are...

Length over coupler pulling faces 59'2" (HO scale 8.15")
Height from top of rails (track) to roof 15'2.5" (HO scale 2.09")
Width 10'2.5" (HO scale 1.4")

If this were to be an actual HO scale model of said engine, the measurements should be what I just posted.
However, That engine does not really have a prototype that it was scaled from so to try to determine a scale for it will be almost impossible. This is similar to trying to scale out Hotwheels/Matchbox cars. Both make all sorts of different vehicles that scale out all over the place. I remember as a kid having a matchbox kenworth truck and a matchbox sports car and they were almost the same length. t was years later when I discovered that they never really scaled anything, instead made the product to fit the packaging. Your best solution with the trains you have is not to worry too much about scale and just enjoy what ever you use with them for buildings, scenery etc.
Click to expand...

Thanks! I'll enjoy my trains even more once my next shipment of Power Trains comes in the mail. Until then, I have decided not to unpack any of my existing Power Trains until then other than to measure them.
 
Spiral Storm said:
Okay...Since you are suggesting TT-scale buildings, my next question is this-Are there any web sites or hobby shops you know of which will sell ready-made or easy-assembly TT-scale buildings? If so, how much will they cost?
Click to expand...
Do you know how to use Google? A search for TT scale buildings returns dozens of results. Much of the TT-scale stuff comes from Europe where the scale is more popular than it is in the United States.

Spiral Storm said:
Thanks! I'll enjoy my trains even more once my next shipment of Power Trains comes in the mail. Until then, I have decided not to unpack any of my existing Power Trains until then other than to measure them.
Click to expand...
I am curious. What is accomplished by measuring your Power Trains? It's already been established that they are not made to any particular scale and that they only vaguely resemble prototype equipment. Suppose you know the length, width, and height of every Power Trains engine and car. How will that information be helpful?

Again, I'm simply curious.

- Jeff
 
jdetray said:
Do you know how to use Google? A search for TT scale buildings returns dozens of results. Much of the TT-scale stuff comes from Europe where the scale is more popular than it is in the United States.


I am curious. What is accomplished by measuring your Power Trains? It's already been established that they are not made to any particular scale and that they only vaguely resemble prototype equipment. Suppose you know the length, width, and height of every Power Trains engine and car. How will that information be helpful?

Again, I'm simply curious.

- Jeff
Click to expand...

Yes, I know how to use Google. The only reason I am reluctant in using TT scale buildings for my layout is because there may be certain buildings or structures I am seeking which may not be available anywhere in TT-scale. However, the research I have done so far has produced many positive results, although some of the items I want require more than 50 dollars.

The good news-I've been saving a little money every month in order to have enough to start adding more buildings to my layout.
Once I get my next two sets from Power Trains, I will re-assemble my layout and show an updated picture of it.
 
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