What is longer 2-8-2 or 4-6-2

There is no standard size. USRA Light Mikados and Pacifics are essentially the same size. I think they used the same boilers but all others can be any size.

Pete

Do I need to go to the B&O museum and bring a tape measure?

Echoing what Pete mentioned, there was no set length for a given locomotive. Each road had it’s own needs & requirements that dictated tractive effort, firebox area, driver diameter, cylinder bore, etc., etc, etc,….A Santa Fe Hudson is a Goliath next to a NYC Hudson, yet each road had a specific job for their specific locomotives to do, ……so, yes, you can take your tape measurer to the museum, as long as your using the references to model THAT locomotive. …..

Pat

Nothing says that the Lionel Pacific is 100% accurate.

I believe the Lionel scale Pacific  tooling from the early 2000s may have been too long for certain prototypes. Specifically in the firebox area. This includes the Tmcc k 4....&1/2.

I.e. Lionel recently offered the R&N pacific in Legacy , same tooling. It's too long compared to the prototype.

An Mth pacific might measure out more to your expectations.

Excellent points by all. I guess at this point I just want to know what is the length of b&o 4500 and 5300.

@peter allen 072518 posted:

Excellent points by all. I guess at this point I just want to know what is the length of b&o 4500 and 5300.

I just want to throw in my 2 cents.  I am confused what happen to the picture posted earlier but here is my take.

All the above points are valid.

Let me add one thing that better describe why with "comparable?" locomotives for a given railroad the 4-6-2 might be longer.  Like your picture showed.  Although I realize it was the opposite of the specs from the book.

The most important fact is what the design parameters are for the locomotive in question.

Although they have the same total number of wheels, the 2-8-2 has more drivers, so you would think it should be longer, not really.  The 2-8-2 was a freight loco, so designed for pulling power and only moderate top speed.  To get that result you want MORE, SMALLER drivers with as much weight as possible resting on the drivers.  So any additional support wheels would be tucked in close to the drivers.  Also stopping to add coal was not that big of a deal because these locomotives generally weren't used for Fast freights.  So generally didn't need a huge tender.

4-6-2 were Passenger locos so you wanted enough tractive effort to get the consist rolling, but really were looking for Top speed performance.  The Drivers were huge so the 3 drivers per side probably outside end to end about the same length as the 4 smaller drivers.  The 4 wheel front pilot truck had a long wheel base and farther forward as it was need to keep the train on the track at high speed.  Further forward created more of a moment arm to guide the locomotive.  The trailing truck was needed to support weight and since not as much weight need on drivers was moved back.  Note also the large diameter wheels on these support trucks (to reduce bearing speed at the journal).  Lastly you want a Huge Tender to reduce time spent refueling.

I'm a NYC, fan so while not directly related to your original question, but to explain tender size adding this.  With the NYC Hudson (their MainLine Passenger Loco) if you look at the tender they carried lots of coal but minimal water because they utilized track pans to get water on the fly.  When the original tenders proved inadequate they started using their PT tenders which were absolutely mammoth.

Hope this helps!  I didn't arbitrarily chose my screen name. LOL

Peter allen

The over all length of the USRA Pacific is listed at 68’71/2” the overall USRA Mikado length is 82’. B&O Pacific’s and B&O Mikados should be similar but consider tender lengths would impact the overall length of locomotives. The next factor to consider is the model scaled accurately to the prototype? Manufacturers can and often do take “liberties” with a model’s dimensions. So the short answer (pardon the pun) is the relative proportions of a Pacific to a Mikado, the Pacific should be shorter. The amount depends on tender length and the manufacturers liberties with scale dimensions.  I hope this helps but I’m afraid it just may add to the confusion.

Lee Gustafson

Have you actually tried, looking up the engine blue prints?

The USRA light Mikado and heavy Pacific used identical boilers, so the engines themselves should be at least very close to the same size. However, a heavy Mike might be larger/longer than a light Pacific. Plus as noted, if measuring overall (engine and tender) length, what type of tender is used will make a significant difference.

@peter allen 072518 posted:

Yesterday I  revised my MTH B&O 2-8-2 light Mikado, it looks fantastic!  I put in next to my B&O 4-6-2 Pacific from Lionel. I was not suspired but the Pacific was a bit longer than the Mikado.

A belated "as I suspected."  Heres a comparison of the Mth and Lionel  Pacifics.

This explains the conflicts when comparing size relations to the prototypes vs model manufacturer.

Thanks to a video from forum member Laz1957.

https://youtu.be/7W533qGnN4c

Regarding B&O Mikados, one thing to take into consideration regarding their length is that one class, the Q-4d, had 70" diameter drivers. As a result, it would be longer than the other classes of 2-8-2s on that railroad, which had 63" diameter drivers.

Stuart

the tenders are also a big difference.    I think the later B&O Pacifics got much larger tenders than the originals.   

On the PRR the K4 pacific and the L1 Mikado used the same boiler.    The locos without tender were pretty much the same length.    However, the tenders were a little different.    From the equipment diagrams show the following

Total Length   K4 83 ft       L1   80 ft 9 Inches

Loco wheelbase      K4  36 ft 2 Inches     L1   36 feet 4 !/2 inches

Remember the pacific has a 4 wheel lead truck taking more length than the 2 wheel lead truck on the Mikado.

A source of information for the B&O class in question might be the B&O Historical Society.

@prrjim posted:

the tenders are also a big difference.    I think the later B&O Pacifics got much larger tenders than the originals.  

On the PRR the K4 pacific and the L1 Mikado used the same boiler.    The locos without tender were pretty much the same length.    However, the tenders were a little different.    From the equipment diagrams show the following

Total Length   K4 83 ft       L1   80 ft 9 Inches

Loco wheelbase      K4  36 ft 2 Inches     L1   36 feet 4 !/2 inches

Remember the pacific has a 4 wheel lead truck taking more length than the 2 wheel lead truck on the Mikado.

A source of information for the B&O class in question might be the B&O Historical Society.

The four wheel leading truck on the K4s doesn't increase the length because one axle of the lead truck is behind the cylinders. As your own information shows the locomotive wheelbase of the K4s is 2.5" shorter than that of the L1s.

Stuart

What's with this strange preoccupation with length?

If you go to the first post in this thread, you can see my initial question.

The readers digest version is: over the summer I received a Lionell Pacific. two weeks ago, I received an MTH premier mikado. The pacific is longer, than the mikado. I assumed both were accurate scale models.  
I was very confused why a passenger locomotive would be longer than a freight loco.
I started to do some digging and could not find the length for either. Eventually, I found one book that had lengths for the mikado and the pacific. (B&O diagrams) and it showed the mikado as about 3 feet longer. But I was not convinced.

To boil it all down, the Lionel pacific’s fire box is about an inch too long for it to be in scale (for some B&O)

so that’s what all the Argal Bargal is about.

What I was trying to say was that the extra set of wheels on the lead truck makes the overall length stay closer to the same as the mikado.    You must have length for the those wheels. 

They're models--not the prototypes.

There can be any number of reasons for model length discrepancy compared with prototype plans--not the least of which would be drawbar lengths or even "fudging" of the model dimensions in order to get them to work on our ridiculously-sharp curves.

PeterAllen,

As I and others have shared there are numerous reasons why prototype steam locomotives varied in length, among tender swapping etc. Models have even more reasons and the two manufacturers models you are comparing make numerous compromises to produce their models. If your desire is to have an exact scale locomotives even custom built Proto 48 models will have compromises. Life is short and enjoy what you have. When it comes down to it these are all toy trains.

Lee Gustafson

To be 100% clear, I am in no way complaining about the models I have.
I was simply confused that the model of Pacific was longer than the model of the Mikado. This lead me to the question is which was longer in real life. This lead  to trying to get actual data on locomotive lengths.

I found it bizarre that I could not easily find the length of two preserved locomotives, when other statistics were available.

but at this point I have my answer, they were based on the same boiler and theoretically are very close in length.

however there was tons of variation leading to variation in length.

it’s very easy to find the length of the big boy or Allegheny as they were “relatively” few built compared with a Pacific or Mikado.

again not complaining, simply looking for an answer and the answer is.

it varies.

@peter allen 072518 posted:

To be 100% clear, I am in no way complaining about the models I have.
I was simply confused that the model of Pacific was longer than the model of the Mikado. This lead me to the question is which was longer in real life. This lead  to trying to get actual data on locomotive lengths.

I found it bizarre that I could not easily find the length of two preserved locomotives, when other statistics were available.

but at this point I have my answer, they were based on the same boiler and theoretically are very close in length.

however there was tons of variation leading to variation in length.

it’s very easy to find the length of the big boy or Allegheny as they were “relatively” few built compared with a Pacific or Mikado.

again not complaining, simply looking for an answer and the answer is.

it varies.

You got it right, except, do you know for sure they used the same boiler?  The same boiler size may have been used if they were both built to the USRA standard design as outlined in the second post.

One thing I should have emphasized in my previous post was that Steam Locomotives were all custom UNLESS the were built to the USRA standard.  The vast majority weren't!  PLease study the information on the development of the USRA standard if interested.

When the idea of true "standardized locomotives" really came into being was when General Motors got involved in the Diesel Locomotive Market.  They knew mass production (at least at that point in their history, LOL).  So that is when true standardized locomotives started, and BTW they offered a myriad of options on their standardized designs.

As I stated in my previous post, what the design criteria were for the given locomotive determined its configuration.  As a Mechanical Design Engineer I can assure you that is the way Major Capital Expenditures are handled by Companies.

@MainLine Steam posted:

You got it right, except, do you know for sure they used the same boiler?  The same boiler size may have been used if they were both built to the USRA standard design as outlined in the second post.

Since the previous discussion was about a PRR 4-6-2 vs. a PRR 2-8-2, they both did indeed use the SAME boiler, as designed and built in-house by the PRR.

One thing I should have emphasized in my previous post was that Steam Locomotives were all custom UNLESS the were built to the USRA standard.

NO.  Many, MANY modern design steam locomotives were designed by individual railroads, such as N&W, AT&SF, NYC, CB&Q, PRR, etc., in conjunction with the three builders, Lima, Also, and Baldwin.

The vast majority weren't!  PLease study the information on the development of the USRA standard if interested.

When the "Super Power" era was developed by Lima, the vast majority of the USRA designs went out the window.

When the idea of true "standardized locomotives" really came into being was when General Motors got involved in the Diesel Locomotive Market.  They knew mass production (at least at that point in their history, LOL).  So that is when true standardized locomotives started, and BTW they offered a myriad of options on their standardized designs.

As I stated in my previous post, what the design criteria were for the given locomotive determined its configuration.  As a Mechanical Design Engineer I can assure you that is the way Major Capital Expenditures are handled by Companies.

@Hot Water posted:

B&O not PRR.

You say No when I think you meant Yes, that is exactly what I was saying.  BTW the locomotives built by the major manufactures were designed in conjunction with the purchasing railroads motive power department.

Totally agree with Lima comment.

According to "Classic Trains" magazine, the largest 4-6-2 was the Class E3 that belonged to the Chicago, St. Paul, Minneapolis & Omaha, the "Omaha Road" ( a subsidiary of the  Chicago & North Western). The Class E3 was 87' long, weighed 347,000 lbs and had a tractive effort of 64,600 lbs. with booster. The tenders carried 14,000 gals. of water and 16 tons of coal. The photos show that it was a very handsome locomotive!