Over the past few days, I have seen snippets on TV about tiny electrical currents being passed through pipelines, hulls of Navy ships, etc., all with the comments that this reduces rust and corrosion. Is this technique used at all in the RR museum field? If so, who is a supplier of such equipment? If its not being used, is there a reason it couldn't be? Sounds like a great way to preserve static displays and seldom-run equipment.

stealthnfo@aol.com

> Over the past few days, I have seen snippets
> on TV about tiny electrical currents being
> passed through pipelines, hulls of Navy
> ships, etc., all with the comments that this
> reduces rust and corrosion. Is this
> technique used at all in the RR museum
> field? If so, who is a supplier of such
> equipment? If its not being used, is there a
> reason it couldn't be? Sounds like a great
> way to preserve static displays and
> seldom-run equipment.

Never heard if it used for railway equipment.

This type of induced current is used to counter galvanic corrosion in pipelines caused by potential differences. These differences can be caused by soil conditions, dissimilar metals, and stray electrical currents from other sources. Sometimes, instead of the electric current, a sacrificial anode will be attached to a metal pipeline.

We were just talking today at work (a domestic water company) about cathodic protection (induced current) on a proposed reservoir. My VP of Engineering said that he feels that a good coating inside and out that is maintained will do the job.

Brian Norden

bnorden@gateway.net

If anyone knows of electrifications, recent or otherwise, where electrolysis mitigation and/or power quality had to be addressed, I would like to get in touch with you. We have a double whammy here at TMNY slowing things down in our pursuit of electrification: close proximity to lots of pipelines and a mid-1970's vintage Ohio Brass rectifier that doesn't meet current power quality standards. We're seeking grant money to hire a PE to guide us through these issues, but until such time, any information from others who have faced this is much appreciated.

Trolley Museum of New York
info@tmny.org

> Sounds like a great
> way to preserve static displays and
> seldom-run equipment.

It does sound that way, doesn't it? Don't bother.

This one ripples through the old-car hobby from time to time, as someone tries to sell this as a way to prevent rust. Unless you really know what you're doing, the only area that gets protected is right around the current source, and welds, bolt connections, and other types of connections interfere with the current density, etc. The installations you mention are complex and expensive.

Far more effective and cost-effective is good surface prep, a zinc-rich primer, and regular touch-up of same. (Scratches or breaks in the surface should be touched up quickly, as localized rusting will be much faster there, especially if moisture is present.)

The old saying applies: if it sounds too good to be true, it probably is.

JAC

Evan,

That's been a know problem almost as old as electric railways. That's one reason why Cincinnati made the streetcar company install double-wire overhead. Stray return currents have been reported to follow steel water pipes, fences, etc.

Even today, as you know, there are concerns. Modern day installation of ductile iron water pipes are often placed inside poly bags to help provide a bearier.

Make sure you get a PE who has expereice with electic systems and electrolysis.

Brian Norden

bnorden@gateway.net

PG&E has an electrolysis map of the Bay Area. Apparently it's a real time thing, and they can tell when BART moves a car into or out of the shops at Hayward just by watching the map (the rails inside the shops are insulated from ground).