The new 39662 Insider BR06 locomotive came my way the other day.
I put it on my Märklin C track layout and all the functions worked as expected.
It is my first German 4-8-4 and has a metal body and comprehensive MFX+ digital control.

So it was natural to compare it with another 4-8-4 model which I have owned for a long time.
It is the American Norfolk and Western Railway J class, which was built at a similar time.
13 of the J class were built starting 1941 and the two BR06 in 1939.
So here is a first comparison photo.


The N&W engine is a Key imports model from the mid-1980s made in Korea from brass and is a simple anlogue control.
As you can see the height difference is substantial, the N&W engine being 16 feet.
When it comes to length not including tender the N&W engine is 109 feet as opposed to the BR06 87 feet.
One of the most startling differences is the area of the firebox grate - 107 square feet (N&W) v 51.9 square feet (BR06).
The N&W engine firebox was fed by a mechanical stoker, whereas the BR06 was hand fired by shovel (my guess).

The second comparison photo is revealing of the reasons for the most obvious differences in the build.
Lets face it, the only similarties are in the wheel arrangement and both having a streamlined casing.
The smaller drive wheels (diam. 5'10" - 1778mm) on the N&W were necessary for the very hilly terrain on which it was utilised.
Whereas the larger wheels (diam. 6'7" - 2000mm) on the BR06 could handle the plain routes around the Rhein valley without problems.
The power of the N&W was transmitted through two cylinders, whereas the BR06 had a 3 cylinder drive. How this translated to advantage in either one I do not know.
The N&W cylinder diameter was 27 inches (686mm) which in ordinary mans terms is massive for a steam locomotive.
The BR06 had fairly conventional size with the three cyllinders each at 27 inches (520mm).


The challenges for the N&W locomotive designers were the long distance running required and the gradients to be faced.
Norfolk to Cincinatti is across the Blue Ridge mountains 612 miles (984km) compared to Hamburg to Frankfurt on a reasonably level 280miles (450km).
The power of the engines was markedly different for this reason and explains the variance in firebox area and other heating surfaces.
The N&W had a power output of 5,100 HP (3800Kw) whereas the BR06 had 2,751 HP (2059Kw).

You might also notice the differences in the connecting rods between driving wheels, both engines being driven on the second axle.
The N&W engine was equipped with huge roller bearings and the rods were made of lightweight high tensile steel.
The BR06 on the other hand had traditional plain bearings and standard steel rods.

I am very fortunate to be able to own these two beautiful models which both represent a pinnacle in steam locomotive design.

Kimball

Edited by user 20 November 2022 21:26:34(UTC)  | Reason: Added info on drive rods and cylinders