I found a 2011 "standards" document for Amtrack passenger cars, that shows all the requirements for passenger cars. One of them is that trains of the cars must be able to negotiate curves of 250 foot radius! Converting that to N scale, it calculates out to 250/160 X 12 = 18.75 inches! So, if your layout holds curves to 18.75" or larger, you can confidently say "the curve radii on my model railroad are complaint with actual Amtrack standards"! By the way, another interesting specification is that each car design must be tested to 125 mph "on all class of track from FRA Class 1 through Class 7", even though operating speeds will obviously be much lower, and, furthermore, "Track quality shall be the minimally compliant for each class of track, per FRA regulations and AREMA standrards" ! Interesting. Jim G
If you dig a little deeper you'll find out that much like we run into, the curve you can push a car around (with a front-end-loader) is a lot tighter than you can run cars either coupled to a locomotive or coupled to a full train. What Amtrak is concerned about is getting them into and out of shop tracks without damaging anything, not necessarily operating on those curves. But yes, that's the specs I've seen as well. Another major issue we forget about as modelers is the vertical curves. You'd be amazed how 'low' some passenger cars are to the railhead, underneath, so that going over a diamond crossing or an abrupt hump can grind them onto the rails like a lowboy with a bulldozer on it. And yeah, Amtrak doesn't want to be worrying about whether a car is going to come apart on the Northeast Corridor. If it's Amtrak, it's certified to 125mph. Period. Which is one of the major impediments to vintage private car restoration, so you know. Go into http://www.aaprco.com/
And this is serious stuff. A buddy runs a private varnish leasing operation. He had an otherwise-inspected car break an axle at track speed (79 mph) several months ago that fortunately stayed on the rails. It could have been super-nasty. Needless to say, Amtrak is elevating their scrutiny in this area.
If I had a room 1/160th the size of the northeast corridor, I wouldn't be able to afford enough track anyway.... Until then, it's running!!! Yay.
.... Until then, it's running!!! Yay.[/QUOTE] And that is what really matters isn't it. Think I'll go run some too.
That's still a lot bigger radius than the 9.75", or 130' full size, that a lot of N scalers expect everything up to and including Big Boys to run on.:wideeyes:
The "Dockside" steam switchers were often used on otherwise very tight radii as was the Alco line of switchers that were created to replace these old tank engines. Both the "Dockside" and the diesel switchers could handle, albeit at low speed, radius curves as small as 50 feet, which many years ago was far more common than many people would believe. When it came to industries within larger cities the space available for gaining a rail siding was often very restrictive, making it a necessity to have very tight curves. A modern day example (well, within the past 20 years) was the Los Angeles Jct. Rwy. When ATSF went to replace the lines' ALCO switcher fleet (a couple of S2s with the rest being S4s) they encountered a number of problems when accessing some of their industrial sidings with the rebuilt GP7s and GP9s that they sent. As it turned out they couldn't negotiate some of the spurs because of tight radii. The parent line then sent the CF7s and they worked like a charm (ironically one being purchased on the secondhand locomotive market). The same was true of the Morrison Knudsen LNG units... the ability to handle tight industrial radii was incorporated into their design, but sadly the car loading on the LAJ is but a fraction of what it use to be. I remember heading home from my Grandmother's house and catching the evening transfer along the L.A. river at the crossing on the north side of Atlantic Blvd. bridge making a 100-car delivery with a single ALCO switcher to the Santa Fe, with this being a very slow process because of the length of the train. I thank God my Dad was also a lover of trains!!!
Even the Santa Fe eventually realised that if you have tight radius curves you can't expect to run anything other than the smallest locomotives.
I understand a Big Boy will go around a 287' (20 degree)radius curve (21.5" radius in N scale) but only at DEAD slow speed. Mainline curves are 573' radius(10 degrees) and larger. The 573' radius is 43" in N scale. My 27" radius mainline curves are considered very broad by model railroading standards, but are very tight by prototype standards. Glenn
