True! What does IRM run? Is that trolley wire?

If you're talking trolley lines. almost all steam RR's ran under wire - at grade crossings. Most trolley lines used 600 Volts DC; a few 1200 volts. Trolley lines were SUPPOSED to be 22 feet above the rail at crossings to clear RR personnel and equipment. They had wire guards crossinf Main Lines (SEPTA does NOT have a guard when crossing the CSX Balto-Phila Main Line in Darby PA)

Since the thread began with reference to PRR and RDG wires, both high-voltage AC (11,000 Volts) the trolley crossings are much different animals.

Phil Mulligan

Ah! A chance to post something I’ve been pondering over for years.
I too was present one misty morning at Lehman place back in the 80s, watching and waiting for the departure of the double headed mainline excursion. As the smoke from the two engines, which were standing waiting for permission out, wafted up, in and around the catenary, I witnessed an unusual sight. Hard to describe, there was some sort of reaction that was visible in the smoke. Almost like the EMF between the wires became visible in the smoke. There was no arcing or flashing or sound, other than the buzzing of the insulators in the fog. It appeared to flicker, or flutter at high frequency, like something on an old tv screen with no signal. I witnessed this phenomenon again many years later under different circumstances. Smoke from a track side factory of some sort was wafting down into the cut where I was operating my train. As the smoke came down over the catenary, illuminated from low sunlight, I saw the same weird activity between the wires. I’ve never spoken to anyone else who has experienced this. Thoughts?

A bit fuzzy on this, but I remember reading years ago that steam locomotives that regularly ran into CUT in Cleveland had to have bell ropes made of cord instead of steel. This was in case a bell rope broke and whipped up into the 3Kv DC. I believe this applied to both NYC and NKP power.

You're seeing effects of corona discharge; the 'lines of the electric field' around the charged conductors in the catenary. The 'flicker' was visible in the field reversal of the 25Hz AC; you might still see flicker at 60Hz if you're sensitive to it (as I am, being heavily nearsighted) the same way you can see flicker in old computer monitors with 60Hz refresh. (Even at 72Hz the effect is not really visible, but no commercial power runs at that frequency, and railroads didn't adopt 400Hz aircraft power...)

If you have ever seen the action of an 'ionic breeze' air-purifier with electrostatic precipitation, that's the same action: the particles in the smoke may have picked up magnetohydrodynamic static charge, and move along the field lines.

If you have ever seen those fat blue-violet sparks that occur when testing or setting safety valves on modern steam locomotives -- that's MHD too.

Thanks Mr Ellsworth for your erudite explanation. I knew someone on this site would have the answer.

At the risk of drifting even further from the OP's question....


And some railroads ran steam underneath both their own electrification and a trolley line at the same grade crossing. For something less than a decade in the 1930s, the Reading's 11 kV catenary intersected with Philadelphia Rapid Transit trolley route 55 at the York Road crossing in Willow Grove. As it was explained to me, the RDG's MU cars had to coast their pantographs through the crossing. The streetcar's conductor, who had to flag the crossing anyway, had to throw an electrical switch to energize the 600-volt trolley wire and then throw it back once the trolley had crossed the tracks. RDG steam locomotives running up to New Hope passed beneath all of this.

The PRR's electrification had a similar short-term arrangement with the Schuylkill Valley Traction trolleys at DeKalb Street crossing in Norristown. That crossing was later grade separated coincident with the Reading electrifying their parallel suburban service to Norristown. Both the RDG and the PRR ran steam locomotives destined to Reading and beyond under catenary as far as Norristown, which is where the attached photo was snapped.

Somewhere, I've seen a photo of the intersecting catenary and trolley wire at the Willow Grove crossing, but can't seem to find it now.

/s/ Larry
Lawrence G. Lovejoy, P.E.

Don't forget the PRR/ WB&A crossing near Odenton ,Maryland. PRR's 11,000 volts vs WB&A's 1,200 volts. And steam (at least on PRR) ran under these in Maryland.

A current example of this is where the Oregon Pacific RR crosses the modern-day MAX Orange Line light rail in Portland, OR, directly adjacent to the ORHF's roundhouse (home of SP #4449, SP&S #700, et. al.).

Said steamers make occasional trips down the OPR, especially during the holidays, and said trips may indeed increase now that there is a pending sale of this line from OPR to the ORHF.

And an interesting historical additional note, is that this line was originally the Portland Traction interurban line from Portland to Oregon City (and elsewhere), meaning that it is a rare diamond of a former transit line crossing a current transit line.

This is correct, and is actually a special instruction in my 1937 RDG Philadelphia Division Timetable. There is one other grade crossing listed in Philadelphia (22nd Street), which I cannot seem to find. It could've been on the Norristown Line pre-grade separation, but then that would mean pre-electrification, wouldn't it?


I have seen a photo of the PRR crossing in Norristown. I'll attempt to find it.


Please let me know if you can find this! We can arrange a trade.

In doing some back-of-napkin math with a knowledgeable coworker, we were able to determine that the smokestack would need to be within ~6 inches of the bottom of wire to pose any serious threat for arcing. He posited that steam exhaust itself was never a concern because its two main components are 1. Nearly pure water vapor and 2. Carbon. On their own, neither of these things are particularly conductive. Tap water is conductive because of the minerals and additives inside, but since the water is being boiled, it is coming out with few if any of those minerals. As I've been researching steam locomotive operation in the last few months, I've managed to determine that water purity and "hardness" were a concern for this exact reason, leading to things like the so-called "Shambles Ramble".

Larry, do you think that this research could count towards my PE?
Sincerely,
Liam McGrath, EIT

22nd Street would have been the intersection of the Reading's Norristown line with PRT trolley route 33. (This was, technically, the Philadelphia, Germantown & Norristown Railroad, one of the RDG's scores of underlying leased or partially-owned subsidiaries, and one which actually predated the charter of the Philadelphia & Reading.) Per the dates cast into the concrete bridge abutments (see attached photo), the Reading's grade separations of 22nd Street, 21st Street, and Allegheny Avenue were constructed in 1939.

So yes, there likely were intersecting 11kV/600v wires at 22nd Street for a while. Less clear is the situation at the PG&N's nearby crossing of Allegheny Avenue - trolley route 60. PRT's 1934 service map shows that 60 was then split into east and west sections with the dividing line where the RDG's Norristown line and the PRR's Chestnut Hill line crossed the avenue. A deep dive into the City's construction photos for that project might be educational.

I might have rescued the mold used to cast those diamond shaped dates from the attic of Reading Terminal except it was too large and heavy to carry home on the Crestmont Local.

Alas, engineering history probably doesn't count as engineering experience.

/s/ Larry
Lawrence G. Lovejoy. P.E.

It's not a rail/trolley intersection, but this popped up on Shorpy the other day.
https://www.shorpy.com/node/27637

I have no desire to climb a tender that tall to fill water, even going up the back instead of over the coal pile. Too close to the wire!

There have been Internet photos, probably on FaceBook, of Philadelphia Rapid Transit Rte. 33 trolleys' grade crossing with the Reading Company's electrified line at 22nd St. (now Allegheny Ave.) station and and aerial photos from the same years of Allegheny Ave. interrupted at 21st. St.
There may have been another wire and wire crossing for a very short time in Norristown, Pennsylvania at the Reading Company's Main St. station with Reading Transit & Light Co. trolleys.

The Allegheny Ave trolley line was split at the PG&N crossing. 60 was the primary route to Richmond St to the East and 60A was a stub route to Ridge Ave to the West. Passengers changed cars by walking across the RR.

60 route remained with double-ended cars until 1955 when it was converted to...PCC's

Phil Mulligan