Saturday, February 11, 2012

Security Blanket

The day started with more paint removal from the 36. Just to keep Kirk happy, I spent some time removing paint from the chamfers in the siding. I never got around to taking a picture of the results, it would look just like all the others.

Then I wanted to check on the tarp I had installed on the 321 last time, so I trekked out across the frozen steppes along the tracks of the Trans-Siberian. As my nose started to freeze off, I began having second thoughts, but inspired by the heroic example of Roald Amundsen I soldiered on. The new tarp is still in place, and I attached some more straps. In between the cars there's no wind, so it wasn't too bad.

Ah, but later there was good news.

This may look like a roll of indoor-outdoor carpeting, but it's actually a fiberglass blanket designed to protect against welding arcs. Rod found it at McMaster Carr and bought us a roll of the right size. This is just what I needed to continue progress in getting the 36 operational. I've forgotten exactly what it's called, so I hope Rod can fill us in.

These first-generation contactors were mounted in wooden boxes, since the contactor frame is energized. Here we see a box on the 36 as it came to us from Cleveland. The sides of the box were originally covered with an insulating blanket of fireproof material, so that if the contactors draw a large arc for some reason it won't set the box on fire. It was attached with carpet tacks, and needs to be flexible to conform to the surface of the box. And you need to be able to cut holes in it to pass the wires into the box. The old insulating material was removed at Cleveland and needed to be replaced with some more modern substance. They also removed the leather straps holding the wires in place, so I had to replace those too.

Installation is not all that difficult. I started by cutting small pieces to shape for the ends of the box. Here's the first piece. I try to follow the original pattern of tacks. However, if you follow it too closely, you're trying to drive the new tack through the old tack. That doesn't work. Furthermore, there isn't much room to swing a hammer up inside this box with all the wires. So next time I plan to bring my staple gun.

I finished installing the insulation in the first of the three boxes. I might point out that the back piece is folded up under itself, so there's a double layer near the bottom, where the arc chutes are. This is much better than the picture above, you have to admit. When it's warmer, I'll paint it with a couple of coats of Glyptol, and we'll be ready to start installing the contactors!


Anonymous said...

Vermiculite-Coated Fiberglass & Aramid Fiber

Randall Hicks said...

Thanks, Rod. So there you have it.

It cost $98 for a 5' x 5' roll, which is slightly more than we'll need for this car, so that's not bad in the overall scheme of things. I will probably even have some free samples to give away to anybody who's interested.

Colin said...

Colin Beckwith

Havant, England.

Hi Randall

Thanks so much for this blog page. Info on the pioneering types of control equipment is vary rare in the UK so I really do like the content that you provide. So much of the apparatus used 'over here' came from GE and Westinghouse in the early 20th century. I am particularly interested in your DB-15's. The units in your pictures that have been in service a while seem to have a lot of what seems to be condensed copper on the inside of the arc boxes. Does this make them prone to tracking? I was wondering what you think of DB-15's compared with the later type. I must confess to getting very exited when I see that you have posted new pictures of control equipment on your blog. My own work with control equipment involves design and build of miniature contactors and reversers as it's difficult to get my hands on the full size items.


David Wilkins said...

For those of you playing at home, Vermiculite is a natural mineral that is mined from the ground and known for its fire-resistant properties. It should not be confused with that other fire resistant, naturally-occuring, mined mineral that can be dangerous.....

Randall Hicks said...

Colin: Thanks for the interesting questions. Yes, the insides of the arc chutes often have condensed copper. This needs to be watched, and at the annual inspections we try to clean them off as much as possible, and recoat with Glyptol. I've wondered whether the magnetic blowout feature makes this problem better or worse, but there's no easy way to find out.

The DB-15 was the first really successful MU contactor, but the later designs are definitely an improvement, I'd say. They're generally lighter in weight, can handle more current, the tips and arc chutes are simpler, etc. I think most of us would agree on that. But the DB-15s are reliable, and of course we have no plans to replace them!

Colin said...

Colin Beckwith

Hi Randall

Thanks for your reply.

It's great that you keep these vehicles running with their original gear. The experience that you describe about maintaining your equipment gives an insight into engineering history that cannot be replicated by any number of pictures or static displays. Having said that your pictures give me an insight I have not had anywhere elso so far on the internet.

In England we have scrapped most of our electric trains. Very little of the really historical equipment remains or is innaccessable. Out of 2000 odd vehicles once used on the Southern Railway here, one survives. This vehicle is static and there is no normal access inside for the public. This vehicle was developed from the very first days of 600v dc practice in England in which the control equipment was built under licence by The British Westinghouse Company. Even the London Underground's vast stock of GE 66, GE 69, GE 260 as well as many Westinghouse items have all but disappeared.

In England we have a very large steam preservation scene, which is good. If as much luck and effort had have been put in with electrics it would be even better. Unfortunately this did not happen as electrics did not seem to have the 'romance' of steam locos.

Good luck with your efforts and thanks

Anonymous said...

Even the London Underground's vast stock of GE 66, GE 69 have all but disappeared.

< weeping >

Randall Hicks said...

Yes, I noticed that too. But what can you do? Where would the money come from to buy and ship those motors back here?