rees@apollo.uucp (Jim Rees) (09/16/85)
This is a rambling account of how track is installed today. If you aren't interested, skip it. Every day I ride the Lowell branch of the Boston and Maine railroad to work and back. This line claims to be the oldest public railroad in the USA, having been built in 1823, and contributed to the demise of the Middlesex canal, which it still parallels in places. For the last couple of weeks I've been watching the crews replace the rails at the West Medford station. I thought rails were put in by teams of sweating men with big hammers taking turns swinging at the spikes. Not so in today's high-tech world. The rails they are replacing were temporary ones that I also watched being installed about a year ago. At that time, they brought in these sections of track already attached to ties. Each section was about the length of a flatbed car, which is probably how they were brought in. The sections were just put down on the ground and bolted together. Easy! The new rails are each about a mile long. They are apparently welded together at the factory, then loaded on a mile long train, each rail running the length of the train, and brought to the place where they will be installed. The rails are flexible enough that as the train goes around a bend, the rails just bend with the train. The old spikes are removed by a big machine, the old rails pushed to one side, and sold for scrap. Some of these rails will end up at the Kennebunkport trolley museum. I talked the crew into giving me one of the old spikes as a souvenir. In this case, the ties were almost new, so they weren't replaced. Some new ballast (the course gravel that the ties sit on) was shoveled in where there were low spots. The crew put the new rail onto the ties, then they run this amazing series of machines over the track. One of them apparently positions the rails so that they are parallel and the right distance apart (4' 8.5" I think). Another one staples the tie plates onto the ties. The staples are a foot long and half an inch thick, and the machine bends them double and drives them into the tie. Just like a big staple gun. The tie plates are those metal plates that the rail sits on. The rails are attached to these by curly metal brackets (anyone know what these are called?) that take the place of the old spikes. You wouldn't want to get your finger caught in the machine that bends these. A couple of questions for you experts. Why is the rail welded at the factory instead of continuous casted? I know it is welded because I can see the welds. My wife used to work at a steel mill, and she thinks it would be possible to continuous cast the rail, although not a lot of mills have the equipment to do this. Also, the old rail had these heat sinks every three ties or so. One of the old-timers who rides our train (which takes B&M employees to the new HQ at Iron Horse Park) says these were needed to keep the rail from buckling on a hot day, although they don't look substantial enough for that. The new rails have no heat sinks. Why not?
mangoe@umcp-cs.UUCP (Charley Wingate) (09/17/85)
In article <28f8b018.1de6@apollo.uucp> rees@apollo.uucp (Jim Rees) writes: >The new rails are each about a mile long. They are apparently welded >together at the factory, then loaded on a mile long train, each rail >running the length of the train, and brought to the place where they will >be installed. The rails are flexible enough that as the train goes >around a bend, the rails just bend with the train. "Continuous" used to be 1/4 mile in length. Has it gotten longer? >A couple of questions for you experts. Why is the rail welded at the >factory instead of continuous casted? I know it is welded because I can >see the welds. My wife used to work at a steel mill, and she thinks it >would be possible to continuous cast the rail, although not a lot of mills >have the equipment to do this. The rail has to be rolled somewhere along the line to give it strength. The Russians probably do continous cast and roll rail, since they've done some neat work with plastic deformation, but, given the demand for rail in the US, and the cost of building a specialized plant, I'm not too suprised that the steel makers keep rolling billets. >Also, the old rail had these heat sinks every three ties or so. One of the >old-timers who rides our train (which takes B&M employees to the new HQ >at Iron Horse Park) says these were needed to keep the rail from buckling on >a hot day, although they don't look substantial enough for that. The new >rails have no heat sinks. Why not? As I understand it, as long as it isn't too hot (like >90 F), you can lay continuous and not have to worry about buckling. (if it's too hot, when winter comes the contraction will pull everything off) So the OT is probably right about the perceived need for heat sinks, but they've since decided that they are unnecessary. Charley Wingate
cb@mitre-bedford.ARPA (09/17/85)
I was on a railfan trip to the B&M's main shops in Billerica a few years ago and got a chance to see how the B&M makes some of their continuous welded rail. They have a welding machine that connected the end of one length of old rail to another. As the (growing) length of rail came out the back of the machne, it was loaded onto gondolas for eventual delivery to the M of W crews. I guess this was an attempt at rail recycling. I don't know if the B&M still uses this machine for some of their rail or if they buy it new. Christopher Byrnes cb@Mitre-Bedford.ARPA ...decvax!linus!bccvax!cb.UUCP
cb@hlwpc.UUCP (Carl Blesch) (09/18/85)
> This is a rambling account of how track is installed today. If you > aren't interested, skip it. No, I'm very interested. That's one of those things I've always taken for granted in the past -- that the track was/is/will always be there. > The new rails are each about a mile long. They are apparently welded together > at the factory, then loaded on a mile long train, each rail running the length > of the train, and brought to the place where they will be installed. I've always wondered how thermal expansion is allowed for in welded rail. If expansion is a linear property, the gap at the end of each mile would have to be quite a bit bigger than the gap at each end of a short piece of traditional bolted rail to accommodate the expansion of a mile-long piece of rail on a hot summer day, right? In freezing cold weather, then, I'd think the gap would be so wide as to invite damage to the railheads, if not to the train itself. Can anyone explain this to me? > The rails are attached to these by > curly metal brackets (anyone know what these are called?) that take the > place of the old spikes. I've seen these on rail attached to concrete ties, but not on rail attached to wooden ties. I've seen extensive use of concrete ties and these curly metal brackets in two places -- the Canadian National's main route through British Columbia and Amtrak's Northeast Corridor. Carl Blesch
jis1@mtgzz.UUCP (j.mukerji) (09/19/85)
> The rails are attached to these by > curly metal brackets (anyone know what these are called?) Those curly metal brackets are called Pandrol Clips (why I don't know). Amtrak has been upgrading its track on the NorthEast Corridor (NEC) between Newark and New Brunswick in New Jersey to 120 mph standard. This involves relaying the existing track, which consists of Continuously Welded Rails (CWR) on wooden crossties. The new track is of new CWR on concrete crossties. The operation is quite a site to watch. To a casual observer it appears as if no human hand touches any of the track material at all. The operation begins with laying out the new CWR along the track that is to be upgraded, one rail on each side, as described in Jim's article. Then comes this giant machine, which is more than 100' in length, which does the following: It firsts pulls out the spikes in the old track, then it pushes the old rail aside, lifts the old crossties and replaces them with new concrete crossties, which are fed into it from a train of flats, which carry them in racks. The new ties are replaced by the old ones on those racks. Then rail chairs, made of what appears to be a rubberlike material are placed on the ties. The two new rails are then pulled in from the sides and placed on the chairs and temporarily clipped in place. That completes the work of this contraption which runs partly on the track that it is about to uproot, partly on rubber tires, where it is doing the uprooting, and partly on the new track. Oh yes, it also clears out all the ballast and creates mounds of them on the side of the track. This machine is then followed by a ballast cleaning and relaying machine, which consists of a long string of gondolas with conveyor belts running all along the length of the train. The ballast that was thrown to the side is picked up cleaned and mixed with new ballast and layed out on the track by this machine. Finally comes the track alignment and tamping machine, which packs the ballast under the track, aligns the track, fixes the guage within required tolerance (I have heard a rumor that the gauge tolerance is less than an 8th of an inch for 120mph), and does the final clipping of the rails in place. Once that is done the track looks very different, what with white concrete crossties and all. Of course, wiring up the track for cab signalling and all that still remains to be done, but that is a much less visible operation. What amazed me though, is that almost as soon as they finish a complete section between two interlockings, they run a test run or two on the new track, they run a track geometry car in at least one of these test runs, and then the next thing that you see charging down the track is a New York - Wahington DC Metroliner!!! Very impressive! They started this relaying operation from the Newark end. The new tracks begin at the East end of the old CNJ overpass, east of Hunter interlocking, and proceed eastwards. Only tracks 2 and 3 are being relayed. The last I saw it, which was last weekend, they were at Rahway station. I am told that they plan to finish relaying this section upto New Brunswick by November. Apparently, this is the last non-concrete crosstie section in the NEC, barring of course, places like the B&P tunnel approach in Baltimore, and such. In general track 2 and 3 have been relayed almost completely between New York and DC. In some places track 1 or 4 have been relayed also. Amtrak has come a long way since its inception. They have got a real passenger railroad running in the NEC. To ride a Metroliner at 120mph on these new tracks is quite an exhilerating feeling! If you plan to be travelling between New York and Washington DC, try it. You'll like it! Jishnu Mukerji AT&T Information Systems Labs. Holmdel NJ 07733 ihnp4!mtgzz!jis1