Tender Drive Wheels?

[red rooster]

Hi all, I just watched a TV program about the New Haven RR  in the transition period. Of course, they we're showing a lot of steamers and early diesels along with some electric motors. There was one steam locomotive and tender that caught my attention because it seemed that on the rear truck of the tender the wheels were attached with what looked like drive bars. It was a quick motin shot that only lasted a few seconds. Does anyone have any idea what these drive bars were for?

[eagle1030]

I would hazard to guess a tender-mounted booster.  I'm not a New Haven expert though, so don't quote me on it.

[Norm48327]

Boosters.

http://en.wikipedia.org/wiki/Booster_engine

[Overmod]

red rooster

There was one steam locomotive and tender that caught my attention because it seemed that on the rear truck of the tender the wheels were attached with what looked like drive bars. It was a quick motin shot that only lasted a few seconds. Does anyone have any idea what these drive bars were for?

Bethlehem Auxiliary Locomotive.

These allowed some of the tender's mass to be used for adhesive weight (the usual 'booster' was mounted on the locomotive).  They were primarily used for slow-speed work (hump service, ore service, heavy transfer).  The inertial 'hammer blow' forces from their outside rod arrangement meant that they were not stable at speed higher than (IIRC) about 17-20mph, so their use on normal road power was limited.

I haven't yet found an online copy of a manual for one of these, but there are copies available on eBay.

[Overmod]

red rooster

There was one steam locomotive and tender that caught my attention because it seemed that on the rear truck of the tender the wheels were attached with what looked like drive bars. It was a quick motin shot that only lasted a few seconds. Does anyone have any idea what these drive bars were for?

Bethlehem Auxiliary Locomotive.

These allowed some of the tender's mass to be used for adhesive weight (the usual 'booster' was mounted on the locomotive).  They were primarily used for slow-speed work (hump service, ore service, heavy transfer).  The inertial 'hammer blow' forces from their outside rod arrangement meant that they were not stable at speed higher than (IIRC) about 17-20mph, so their use on normal road power was limited.

I haven't yet found an online copy of a manual for one of these, but there are copies available on eBay.  Here is a reference that you may find useful if you want to do further research.

[red rooster]

Thanks all for the information. Never heard of this before, very interesting.

                                                                                                          Jack