Concrete junctions

[NDORFN]

Does the US have concrete junctions or do they still use wood tie even when it's on a concrete tie section? I'm extending a siding on my route using concrete ties (because that's what other prototypical upgrades on the line used). Just wondering what they'd use to make a brand new junction.

[SCLALINE]

in my opinion they are rarely used but here is a forum post with some on a transit line
http://www.railroadforums.com/forum/sho ... hp?t=30812

[NDORFN]

Thanks for that. I think I'll stick with wooden ties. I've seen a few pictures of concete tie'd track being laid with wooden switches so I guess it's still the most economical option. That's what they're doing here in NZ except on commuter lines where everything is concrete.

[SCLALINE]

may be a strength issue as well

[NDORFN]

Yeah. I'd have thought that concrete ties would hold thier shape better providing a smoother ride for passengers but would be susceptible to fracturing under heavy loads.

[NS9030]

There was recently a new CSX intermodal yard built in north Baltimore, Ohio and he new junctions west of the yard in Hoytville were replaced with concrete ties.

[_o_OOOO_oo-Kanawha]

You mean concrete switch crossties?

Overhere in the Netherlands they have been standard for the past couple of years. I don't know the real reason, but it could be environmental, no more hardwood, no more creosote.

Instead pre-stressed reinforeced concrete ties are used. Requires completely different logistics as they are several times heavier and bulkier than previous wooden switches. Prefabricated, cut and drilled by CAD/CAM in advance on the drawing computer and production lines of the contractors. Concrete switches and very complicated yard tracks and ladders come partly pre-assembled in kit form to the location, pieces of rail, frogs etc. usually in place. The pieces are laid out and put together model railroad style on nearby flat ground and the larger sub-assemblies then lifted in at night. Usually this means complete closure of the line/yard, temporary removal of catenary wires, temporary access roads for the huge auto cranes required when rail cranes are impractical. Specially designed rail cranes which can operate under live catenary but their capacity is limited only to small sub-assemblies. and they need adjacent/parallel tracks to run to and fro. So far I haven't seen wheeled/caterpillar tracked "rolling bridges" that carry complete switches, several tens of meters long and weighing more than 100 tons i use in rebuilding under constrained circumstances. These vehicles are reserved for "maiden" track on large projects. High precision GPS and laser levels allow for putting the sub-assemblies in place with centimeter precison. Joints are then bolted/welded or glued for isolated track circuits used in train detection. A complicated timetable/schedule of events is needed to put all the pieces together and have trains running again by next morning. Large projects take several days and sometimes weeks to complete and are often combined with complete closure of lines and stations for other rebuilding, overhaul, maintenance during public holidays and school vacations.

In the end concrete trackwork offers better stress and load resistance, longeivity and lower maintenance = when properly laid, leveled and tamped = all lead to lower costs over the long run. To ensure the track does not shift, the side and bottom surface of the switchties are often serrated. Someitmes metal "anchors" are tamped right deep into the ballast to fix the outer edges. Complete and permanent fixation by casting a concrete roadbed instead of pouring ballast has also been tried but not repeated, probably due to weak soil.
In the beginning there were some problems, mainly rough riding and derailments over complex yard trackage involving double slips and reverse curves, due to the inherent "rigidity" of the complexes as a whole. Yard speeds have been reduced from 40 to 30 km/h as it is almost impossible to redrill the switchties. Flexible wooden ties and bolted joints allow for a more natural settlement of the track and over time deform into a "natural" transition which was unaccounted for on the design tables at first. With CAD/CAM the design rules and geometry can be easily adapted, different fastening hardware allows for small adjustments. With the current cost cutting trend towards "directional" operation of many of our main stations the need for the complicated trackwork that prevously allowed trains from all directions to arrive and depart from every platform track no longer applies.

See here for a Google Maps view of Utrecht CS south yard. Notice the partly assembled switches. I travel Utrecht-Arnhem daily and have seen the slow progress over the last decade. Some of these yard switches move every minute, failure leads to nation wide service disruptions.
http://g.co/maps/s7jfg

Complete rebuilding of Utrecht CS, the most important hub and station in our network has been going on for decade and will last another 5 years. Total cost in excess of Euro 1 billion for it involves a lot more than just the station. The two double track main lines emerging South from here to Arnhem/Germany and 's Hertogenbosch/Southern Netherlands see up to 10 trains per hour each direction and are planned to be quadruple tracked the coming decennium. Works are already well underway between Utrecht and Houten, numerous new underpasses beweeen said stations allow for this directional operation and provide for cross platform connections for passenger convenience. The three large river crossings south of Houten will provide the future bottlenecks as they require allocation of several 100 millions of Euros each, so will remain double track for the forseeable future. The line to Arnhem/Germany has been postponed for complete quadrupling and will be done in segments. It was to be a part of the proposed high speed corridor (London-)Amsterdam-Frankfurt-Basle/Vienna/Prague (Switzerland/Austria/Italy/Eastern Europe/the Balkan States). The line going north to Amsterdam has already been quadrupled, West to Gouda/The Hague/Rotterdam is under construction.
That leaves only the important mainline going East to Amersfoort/Zwolle/Deventer, which also sees 10 trains each direction but cannot be rebuilt past Blauwkapel Jct. because there is no room in its densely built-up narrow corridor through Bilthoven and Den Dolder. NIMBY policitcs of the upper middle classes that reside there so far have blocked any solution. Complete covering of the line is probably the only option but given the commercial failure of the high speed underground Heart of Holland link there is currenlty neither money nor polical will to proceed.
Part of its traffic will be rerouted anyway once the new line Den Haag/Schiphol/Weesp/Lelystad/Zwolle is opened next year. This line allows the half hourly intercity services from the western cities of Den Haag (and possibly Rotterdam) going to the north of Zwolle, Groningen and Leeuwarden to bypass Utrecht alltogether. We'll see which lines and hubs next get congested and will have to be expanded and rebuilt. The Den Haag Amsterdam corridor alrady has 4 to 6 tracks and is properly congested during peak hours. There are already plans and works underway to quadruple the Amsterdam/Weesp/Lelystad segment to a proper new northeast corridor. High speed TGV and even Maglev has been proposed in the past to make this line part of a another pan-European corridor Madrid-Paris-Brussels-Amsterdam-Hamburg-Copenhagen-Stockholm but nothing came out of these ambitions.

All of those works and plans are the constant subject of political quarrels and cost cutting measures. Since there is no real commitment to provide for an all inclusive nationwide tranportation policy that will be future proof and pleases everybody.

[NDORFN]

Wow. Simply wow. That not only answers my question but give me something to look at for the next 30 minutes.