Okay, that sounds weird. What I mean is: That's the largest type of steam locomotive this narrow-gauge railway has, and I think it's the most powerful type of narrow-gauge steam locomotive ever used in Germany. But yeah, compared to the converted former normal-gauge diesel locomotives behind it, it's tiny.
Indeed. Also, it's positively miniscule for its 4-8-2(?) wheel arrangement. Normally anything with a 4-8-# configuration is going to be as big as or bigger than those diesels.
As for narrow gauge locos, I gotta admit, most are pretty small for what the same driver configuration can become in standard gauge. Though there are a very, very few very large narrow gauge locos around.
(Actually, it's 2-10-2 in american notation, or 1'E1' in european.)
You're right. It is, of course, all down to axle load. A normal gauge locomotive with the same power output would need much less wheels to get the same weight on the drivers. The diesels in the rear show the same effect in the opposite direction: The normal gauge version has four axles. When they were converted to narrow gauge, they got six (with new bogies) to stay within axle load limits.
The narrow gauge locomotives that get really large are typically in areas where narrow gauge is the only widespread system, and so these lines are built to the same weight limits as normal gauge in Europe or the US. South Africa or parts of Australia are good examples.
Cool. And yet both of our original statements about relative size stand unchallengeable. The White Pass and Yukon Route from sea level from Skagway, Alaska to the far inland end 110 miles away in Whitehorse, Yukon Territory, Canada is a good example of heavy duty narrow gauge with full size diesels that approach a standard GP38 in overall weight but sit on a pair of 3 axle, 3 motor, 36 inch narrow gauge trucks. It's all fascinating stuff. Wouldn't you, as a fellow railfan, agree?
Absolutely! That's the fascinating thing about railways, isn't it? If everywhere had exactly the same trains, then that would be incredibly boring. There are surprisingly many ways to approach the issue, each with their own advantages and drawbacks.