I'm a long time railfan dating back to when I was 5 or so. My rail riding experience is long and varied with many trips on the IC between Chicago and Champagne, on the NP between Chicago and Missoula, MT., on many freights on bothe the GN and NP, and more recently, on numerous Amtrak trains. I've been an expat for th last 11 years, now retired in NE Italy, about 75 miles NE of Venice.
Obviously there are a lot of differences between the two rail systems, but one or two stand out that kind of baffle me. One is that the web and base of Italian rails are painted or whitewashed white, and in the stations, the white extends over the ntire track strcture. Does anyone know what this stuff is and why it's there in the first place?
I have hardly any experience with over head catenary, mostly with the MILW in and around Missoula, MT in the 60's. My recollection is that there was a single contact wire, but what I see here are dual contact wires which appear to be about an inch apart. All of my observations here have been in stations as watching the contact wire at 90 MPH is difficult at best. Are dual contact wires found in the US at all, or maybe I just have double vision?
As an aside, traveling from Trieste northward into Austria I saw a lot of slab track near the mouths of tunnels and over bridges in the Julian Alps on the Italian side. the ride was quite smooth as I recall but was the first, and only time I've ever seen the stuff. There was an article on slab track (continuous concrete with no ties) in Trains a while back, but I haven't seen anything since then.
daveklepper Much of the Italian RR's initial electrification, post WWI, was three-phase AC at 16,000V, requiring two overheads, spaced apart. (I rode one of the few remaining examples, Tirano-Sondria, in 1960.) After II, nearly all were converted to 3000V. DC, which has been the Italian standard, although the new high-speed lines are most likely 25000V single-phase AC, 50Hz. When converting the three-phase lines to DC, it was a lot simpler to simply reposition the existing catenary 25mm apart, than to replace with new catenary with larger-diameter wires for the added current the lower voltage requires. Check out one of the new high-speed liens. I think you will find single catenary. Don't remember the white paint from my last Italian visit some 40 years ago.
There were two systems of AC overhead supply in Italy:
3600 volts 16.66 Hz, and
10000 volts 45 Hz; installed in the early 20th century.
Currently, 25kV 50 Hz is used on high speed lines.
The 3.6 kV system was more widespread and it was mainly this system that was converted to 3000 V DC by moving the wires together since the voltages and currents would be similar.
I travelled from Alessandria to the Mediterranean coast on a train using the 3.6kV system in December 1974. The line went through a long tunnel through the coastal mountain range electrified by AC, and I was amazed at the difference in climate from the cold winter weather inland to the warm weather on the coast.
The Alessandria yard had been converted to 3000v DC, and the train departed with three locomotives, an E626 DC unit and an E552 AC unit leading the E432 which was to work the train onward.
At the first station outside Alessandria, the overhead reverted to AC, and after the train coasted to a stop, the E552 raised its conductors and pushed the now dead E626 out of the way. Allowing the E432 to work the train onward. In Cairo, the first station on the coast, an ex British Army 0-6-0 diesel (700.001) pulled the E432 out of the way and a DC unit took over for the run along the coast.
see https://it.wikipedia.org/wiki/Locomotiva_FS_E.432
In Australia, the sides and base of rails on long welded track was painted white to reduce the temperature rise in summer due to solar radiation on the dark rusty rails. This was confined to sharp curves, but the same principle would apply in Italy. Of course there may be a quite different reason...
M636C
Regard this as opinion not fact. There is a process called magnaflux used to find cracks in metaL. a white paint is applied and cracks turn purple when a strong magnetic field is introduced. Possibly this was tried to find potential cracked rails. Probably a long shot idea.
GN_Fan I have hardly any experience with over head catenary, mostly with the MILW in and around Missoula, MT in the 60's. My recollection is that there was a single contact wire, but what I see here are dual contact wires which appear to be about an inch apart. All of my observations here have been in stations as watching the contact wire at 90 MPH is difficult at best. Are dual contact wires found in the US at all, or maybe I just have double vision? As an aside, traveling from Trieste northward into Austria I saw a lot of slab track near the mouths of tunnels and over bridges in the Julian Alps on the Italian side. the ride was quite smooth as I recall but was the first, and only time I've ever seen the stuff. There was an article on slab track (continuous concrete with no ties) in Trains a while back, but I haven't seen anything since then.
The Milw used two contact wires on their overhead. The hangers for the two wires were staggered, so the hanger for one wire would be adjacent to the low point on the other wire. There were two basic reasons for doing this, one was to collect high current and the other was to improve contact at speed. GE did some tests at Erie in 1922 1923 to see how much current could be drawn and were able to pull 5,000A 5,400A at 60 58MPH (850V).
I recall seeing a reference or two for slab track in the late 1960's, but no recollection since then. Most of the elevated and underground portions of BART are on the equivalent of slab track.
[edit: Changed numbers in my first paragraph after re-reading article on tests in the September 1923 issue of General Electric Review. Tests were carried out in the week of July 16, 1923. The article specifically stated that the twin trolley cncept was originally devloped for the Mlwaukee electrification.]
Slab track is relatively common in tunnels because it reduces the incidence of fouled ballast from leaking water. I would imagine this is a big problem in the Alps and Northern Italy. Slab track can be an advantage, since it can be laid lower than the original track bed and thus increases clearance in the tunnel.
The standard European loading gauge narrows significantly near roof level for locomotives and passenger cars. Even to carry single stacked containers, clearance can be a problem for a 3 metre tall container on a standard flat car. There are a lot of road trucks carried on low level flat cars and these are close to the loading gauge through many older tunnels.
So going to slab track reduces maintenance and can improve clearances at the same time.
On station tracks it is disinfectant due to the use of hopper toliets. Out on the line it is for buckling.
In Netherlands, Belgium, and Italy, all the mainline DC electrifications use double contact wires due to the high amperages caused by the low voltages. (1.5kV in Netherlands and France, or 3kV in Belgium, Czech Republic, Slovakia, Poland, and Italy).
A number of years ago Railway Track and Structures ran an item on the B&LE painting rails white to limit sun kinks. Privately I asked the Chief Engineer if could quantify the benefit, he chuckled and told me he did it as a joke!
There are more stories about him but for another time and over an adult malted beverage.
I would like to thank everyone for their input and help on this. After reading some of the comments I went back thru some older photos I have and taking a closer look at things. I scanned some slides of the MILW in Montana, and came to a strange conclusion. I hopped a NP freight in Wallace, Id to Missoula, where I rode in the caboose up to the top of Mullan pass, then went to a boxcar from there on. We met MILW 263 at Saltese and I got a shot of a Little Joe E74 passing us. It clearly shows two contact wires, but when I compare that to a shot of E73 next to the Missoula depot, it appears that there is only one contact wire. Am I going blind in my old age? maybe so.
Anyway, the white stuff in the Italian stations may indeed be disinfectant since the cars do not have retension toilets. I compared what i see today with a photo i took in Trieste in 2005 on track 1, and it appears that there is no white stuff. I also have taken many trip to Gorizia lately -- the alternate route to Venice via Udine, and the rails there are painted white, which was not the case a few years back. So maybe something has changed in the last few years as i do not recall being aware of white tracks back 8-10 years ago.
The trains I take now orginate and arrive on tracks 5-8 so I really don't see what track 1 looks like now. I'll be going back to Gorizia within a month, so I'll make it a point to look at track 1.
It's possible that the catenary next to the Missoula depot only had one contact wire. The track by the depot was on a 0.15% grade, with grades varying from 0.1% to 0.25% within a mile of the depot, so trains were not going to need a lot of current (except for accelerating).
The picture of the Milwaukee's Missoula depot in Morning Sun Books Under Milwaukee Wires shows a double contact wire on the track closest to the depot, but single contact wires on the two tracks further away from the depot. Other pictures in the book show the main line with double contact wires and side or secondary tracks with single contact wires.
- Erik
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