synonymouse Wrote:
-------------------------------------------------------
> The Rio Grande seemed pretty well committed to
> outside frame after the mudhens of 1903. The
> first order of the 2-6-6-2's for the NdeM in 1928
> is just prior to the 490-499 conversions so you
> have to guess the Rio Grande must have been
> approached by Alco. Especially since the Rio
> Grande had standard gauge articulateds.
>
> Could have been a 2-6-6-2 built to Rio Grande
> specs would have been too heavy for Lobato
> trestle, amongst others. You can't split up an
> articulated the way you can two 2-8-2's.

You bring up a good point on the weight of an articulated locomotive. I am not as
familiar with the K class of the D&RGW as I am with IRCA engines.
During their tenure in Guatemala, the 250-251 were tabulated to have a total weight
of 194,500 lbs. on drivers with 14,400 lbs. on the leading truck and 27,400 lbs. on
the trailing truck for a total engine weight of 236,300 lbs. Just assuming that the
weight was split up evenly amongst the 6 drivers, that'd be about 32,416 lbs./axle.
Loaded tender weight was 83,280 lbs.

I just now located an old spec sheet for 480/490 class locomotives.
480 class had 143,850 lbs. on drivers for about 35,712 lbs./axle.
490 class had 148,280 lbs. on drivers for about 37,070 lbs./axle.
480 class loaded tender weight was 99,500 lbs.
490 class loaded tender weight was 120,000 lbs.

Don't be afraid to check my math...I apologise for any errors that might show up.