Old AHM/Rivarossi 4-4-0 upgrading

[Schraddel]

Hello,

here i will describe what i am doing to modernize this old steamer. Long ago in the 1960's Rivarossi made them for AHM according to prototypes of the famous Virginia & Truckee. These 4-4-0s were then owned by some silver screen companies and well known movie stars.
But in the 1960's made their own type of motor in terms of today relavtively huge and rough running. To get this motor into the tiny 4-4-0 they made 2 bugs to make it possible. First the motor was placed into the tender and second the overall scale was larger than 1:87.


Some years ago this loco came into my posession and because i knew about the bugs i had very little notice about it. Additional there were the tiny wheel of pilot and tender with very deep flanges to made the things more worse.
But because this loco was in the livery of the AT&SF, i paid some attention to it when i became an Santa Fe fan. First try to make something out of this loco was the replacement of the rough Rivarossi motor by an cheap Mabuchi can motor. Therefor the driveshaft to the loco has to be stretched which was don by an piece of white plastic tube. The loco was then running much better, but still not the real McCoy. Main reason was the unreliable current pick up. Optical there were the tiny wheels and the sort of pendulous abdomen below the tender to get the Rivarossi motor into.

I made some comparison with real AT&SF 4-4-0s:
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O.k. here we are, for a scale model of one of the V&T's relative small 4-4-0s the AHM/Rivarossi model is defintive too large. But for an modell of one of AT&SF's later 4-4-0's it will pretty good match. Not 110%, but a good stand-in. So i decided to do something with the old loco.





Here i fitted 33' wheels into one of the tender trucks. Right the old wheels for comparison, more flanges than wheel.





Fist task was to remove the old drivetrain completely. There is an sheet metal plte onto the tender botton wich keep the thread of the truck monting screws. Also this device was former a motor bracket, i bend the brackets from vertical to horizontal because they were no more need for them.





Loco and tender running gear in an intermediate status for testing.





Here too the old drivetrain was completely removed. I purchhased an Mashima motor of suitable size and placed it as shown. As an relative light part the motor was placed above the pilot truck. The axle gear of the first pair of drivers were relaced by an Roco gear wheel with 24 teeth. The worm was direct onto the motor shaft and the gab between was bridged by an idler. The idler was beared loose on a short 2.5mm axle and theis axle was beared into bores drilled into the two pieces of 1.5mm styrene sheet. The two styrene peices were cut in seize so in that manner, they will pinched into the part of the chassis. Thus enabeling to adjust the correct meshing of the gears. Test running helps a lot, noise is a good indicator for incorrect mesh. So when the corect mesh is adjusted through the backdoor, the two styrene sheets were fixed by glueing with CA. But be careful not to glue the idler wheel. All gears were from Roco and out of my grab box.
This was quick and dirty making loco gears.
Of course there more scientific and more techinical and craftmanshipical methods to do that, but it runs.





The loco was then makeshift wired, assembled an analogue test runnings were made again. Note the replaced pilot wheels, the 33' wheels and the disappearing of the tender abdomen improving the impression of the model too. The flanges of the drivers were turned down to meet NMRA Standards.

Cheers Lutz