Today, Wednesday, 16 May, I attended the Spring 2018 meeting of the Israeli Acoustical Society. The meeting was held in the conference room of the new Sammy Ofer "Football" (Soccer in America), and we were given a tour of this huge (36,000 seats!) modern two-year-old stadium in the outskirts of Haifa. A presentation on the use of the Siemens Noise Camera was given, and the flat plate version was actually used in the room to show the color splashes when people shouted or clapped hands, color splashes superimposed on the picture of the room at the points where the noise was produced. Relevant to this Forum we saw a film of the setup of the measuring ssytem along the new line into Jerusalem, with both a diesel-powere and an electric-powered train. Obviously, the diesel was noisier. What was interesting is what noise there was from the electric came from the area of the trucks, probably motor, gear, and wheel-rail interaction noises; but the noise from the diesel was largely from the body, noise of the diesel prime mover and cooling fans.
From the bus leaving Jerusalem and returning, I could see the catenary installation on the new line. Coming back, using rail Haifa - Tel Aviv and the bus from there to Jerusalem, there is no sign of any catenary installation in the Ayolon Corridor used by all trains to access Tel Aviv stations. So, at the present time, the new Tel Aviv - Jerusalem line cannot be operated unless diesel power is used. And catenary installation in the Ayolon Corridor will not be simple because of the intense traffic on this largely only two-track line.
The train from Haifa was from Naharia and was headed to Beir Sheva. It was a double-deck push-pull, non-stop from the Bat Gallin Haifa station, closest to the Stadium, to the T. A, University/North T. A. station.
In the early morning rush hour, I rode the light rail from the Givat Ha- Tachmoshet, Amunition Hill, station to the Central Station. A younster gave me a seat, but about half the passenger count was standing, and it was quite a mixture ethnically and gender-wise. The quietest and smoothest ride of the day. But traffic-light Preemption seemed not to be working everywhere, with two stops for traffic lights been Givat HaTachmoshet and the first stop south at Shimon HaTzaddik.
Israel Railways uses welded rail, not rail joints except where required for signal-system track-circuit insulation or other specific requirements. So why do I hear a low thump -- thump --- thump, along with a tiny vibration as if jointed rail was in use? Do they fail to smooth the welds as seemed o me to be standard practice on North American railroads?
? who makes the welded rail used in Israel and where does it come from.
Russell
Could be a flat spot on a wheelset...
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daveklepper So why do I hear a low thump -- thump --- thump, along with a tiny vibration as if jointed rail was in use?
Assuming four wheel trucks/bogies on the cars, if you're on jointed rail you'll hear "tunk tunk....tunk tunk.........................tunk tunk....tunk tunk.........etc. If you're only hearing one thump at regular intervals, I'm going with Ed's suggestion that there's a small flat spot on a wheel.
Staggered joints will simply double the "tunks", although rail length combined with car lengths will get them jumbled together.
Larry Resident Microferroequinologist (at least at my house) Everyone goes home; Safety begins with you My Opinion. Standard Disclaimers Apply. No Expiration Date Come ride the rails with me! There's one thing about humility - the moment you think you've got it, you've lost it...
I know what flat wheels sound like, and the repetition rate (frequency of thumps) is also much greater. It sounds like the opposed-joint thumping on Euroepan railroads, which in old days was also the case in Israel, but it is much quieter with almost unnoticeable vibration. One has almost to deliberately listen for it. It certainly is not severe enough to spoil the ride quality. It is absent on the light rail line. The light rail line uses girder rail throughout, even where there is no pavement. (Girder rail is streetcar rail with the guard-rail part of the rail, two surfaces even with the surrounding pavement and a flangeway between them, the surface under the treat of wheel about two or three times as wide as the guard-rail surface.)
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