Although there is no restriction in the forum rules, since this listing is unusual, I am making the case why this is train related (Rich please don't bump me):
1) This sale is to raise funds for a train purchase. 
2) This could be used to design a train ( and one like it obviously did get that use).
3) I would rather it go to someone on the forum than into the anonymous universe. This is also a great decoration for your train room.
This is the four foot Pickett slide rule that was probably used in your class room a "few years" ago. I have had this for 15 years and it comes with the original box from Pickett along with instruction manuals. It is wooden and in great shape, the cursor is good, paint is good, etc. I can post more photos if interested. It is hard to figure value but I think this is worth $300 plus shipping -email me if you are interested. My email is in my profile.
original box and instruction manuals
You can see the paint, scales, etc. are crisp
The full four feet long version
No scales on the back
Cursor close up and official designation with scales
