Large Scale Central

Curious about this Big Boy fixture

General Discussion
#1

While running through today’s news highlights i ran across pics of the Big Boy move. The second pic in the series peaked my curiosity, as I’ve never seen the likes of it on any steam engine.

Does anyone know what the chain drive/adjuster is for ?

#2

Just a guess, but that might run the air compressor.

#3

Or it could be operating the bearing lubrication system while the loco is in motion, without steam power from the boiler they would need some other method to pump lube oil while its moving.

#4

Yep, that too. Anybody have the gouge?

#5

Stecve: That maybe an automatic oil pump for the bearings. That is a guess. Paul A

#6

Vic’s right, it is the chain for the lubricator. It is normally covered, though.

Matt

#7

The chain is driving a lubricator. Originally there was an arm upward from where the sprockets are now, with a link between them. At some time UP replaced the links with the chain and sprockets. The chain only moves a short distance, then reverses.

#8

These engines had 4 lubricators driven off the valve gear. Two were for steam oil and two for bearing lube oil.

#9

Here’s a picture of the chain covered up

Matt

#10

Thank you all. I learn new things everyday

#11

Isnt that so you can pedal when you run out of coal?

#12

Bob McCown said:

Isnt that so you can pedal when you run out of coal?

Bob, that’s what I was thinking… :slight_smile:

#13

Bob By god I think that you’r right… Figuring the tonnage, wheel diameter and sprocket size. It works out to a ratio of only 237,618:1. You would be pedaling pertty fast but you could move it.

#14

I figgered somebody would know.

Whoda thunk it! That great big choo-choo, powered by that itty bitty motor cycle chain!

#15

It’s so that little boy can pedal it.

#16

Ah so its original (more or less) to the loco, I thought it was a retrofit for the journey. Good to know that.

#17

Vic Smith said:

Ah so its original (more or less) to the loco, I thought it was a retrofit for the journey. Good to know that.

So, when you build your model, Vic, don’t forget to include it!

#18

Now I would pay to see that. A Big Boy going around the Pizza, the ultimate chasing its own tail.

#19

But Vic won’t have enough room to add a caboose!