Std Gauge track spacing?

Early in our existance SGMA members noticed that some Standard Gauge trains with large overhang and/or large underhang would collide on curves when passing each other on our original 84 and 72 mainlines.  The tracks were simply too close to each other.  We knew we needed to change our standards by increasing the diameter of our outside 84 mainline but how much was the question.  To determine that, a committee of SGMA members was formed to take standardized measurements of the underhang and overhang (as well as various height above center rail measurements), of as many Standard Gauge engines and cars as they could lay their hands.  The committee's objective from this data was to determine what the optimum separation between our mainlines should be to prevent collisions between passing trains. 

Though measurements are still being made, the committee's preliminary results indicated that we needed to change our 84 mainline standard to an 87 mainline standard.  This new 87 standard was quickly adopted and had several advantages over the previous 84 standard.  Not only did it eliminate contact between passing trains on the 72 and 87 mainline curves but it also established between our 72 and 87 mainlines the historic 7-1/2" centers, which now existed between all of SGMA's mainlines (or sidings), i.e., 42, (57), 72, and 87, but had not existed with our previous 84 mainline standard.   Furthermore, the new 87 standard greatly facilitated the installation of crossing tracks between the 72 and 87 mainlines using wide radius (72) Standard Gauge switches.

While the Standard Gauge trains you run on your layout may not have large enough overhand and/or underhang to cause collisions between passing trains on your mainlines, I recommend you consider installing 87 vice 84 curved track.  It is readily available from USA Track, is superior in quality to foreign made Standard Gauge track, and is entirely MADE IN USA. 

Bob Nelson

can i ask you what sort of equipment causes these collisions?  the largest standard gauge cars i have are the Girard passenger set and at ~16" length, they have less than 1" of underhang on 72" diameter curves and i don't believe i have any prewar locomotive that overhangs a 72" curve by even an inch.  is modern (postwar) standard gauge the problem?

Gary, the prewar state set cars have a much longer wheelbase than the girard set. They have the largest underhang on my layout.  Also, the Ives 1764 and 3243 locos have a surprising amount of overhang with their pilot trucks as they come into corners.

But otherwise you're right, much of the problem is with more modern equipment. The Lionel Hiawatha is a case in point.  Also in my experience, some of the largest CMT and McCoy (the Chief Cle Elum) steam engines have a lot of overhang, again on the front pilots.

The largest overhang that I run is the enormous Robert Hendrich GG1, followed closely by the Lionel (MTH) Super 381.  

Unfortunately, the SGMA committee, which took the initial overhang and underhang measurements, has yet to publish/post their initial data on the SGMA website.  For over a year I have tried to get this committee to post their initial data online but they are reluctant to do so claiming they haven't finished their study.  As a result, I don't know which Standard Gauge locomotives and cars of the ones they measured have the largest overhang and underhang measurements.  IMHO, the committee should publish their initial results immediately and then update that data whenever new measurements are taken.  Let's hope that the SGMA measurement committee reads this posting and feels pressured into publishing their preliminary overhang/underhang/height data on the SGMA website.

Bob Nelson

My experience agrees with Hojack's observation that the State cars, the Lionel Hiawatha, and the Super 381 are the most problematical of any Standard Gauge equipment that the average operator is likely to encounter. I would also take a look at the McCoy Cascade - no significant overhang there but it looks like it might have quite a bit of underhang. 

The Hiawatha cars, which appear to be based on State cars, have a lot of underhang. The grab irons on the baggage car stick out even farther. I once had to relocate a bunch of tunnel supports on a museum layout because the baggage car grab  irons fouled them, even though the rest of the car cleared fine. An original State set had been negotiating the tunnel without problems, so it appears the Hiawatha cars require more clearance than the State cars.

I've also been told that the Rich-Art Bi-Polar is a giant for both overhang and overhead clearance, but those are sufficiently rare and expensive that I've never had my hands on one. 

A related issue to consider with very large locomotives is the strength of bridges. The Hiawatha is very heavy, and it comes with a notice to check the strength of bridges, etc. before attempting to operate. 

I endorse what others have said about using 87" rather than 84" curves. It costs the same, and it gives you a little bit of extra clearance that might just come in handy some day. 

Thank you for the quick replies. I will use the 87 curves and keep at least a 7.5 inch spacing. Do you think I can get away with narrower spacing on the straights?  

Thanks,

Bob

Thanks for this info on track spacing.  Maybe this Christmas I will run two trains.  Anyway,it seems that running two standard gauge trains that the large gap would look just right.

I remember when you guys were in Monroeville a couple of years ago,your layout was spectacular.  I hope that you can return.

Norm

Bob, it seems reasonable to expect that the tracks can be closer together on the straights, since much of the need for the extra space on curves comes from equipment overhanging to the outside of the curve and/or inhanging to the inside of the curve.  However, no one seems to have actual numbers for either curve or straight track spacing, since there are so many unknown variables.

If at all possible, have a sample of your largest/longest/most-overhanging equipment handy when you are laying the track, and keep checking as you go.  The more space you can allow, the less chance there is in the future of having a newly-acquired model cause problems.

That seems to be about the best we can do at the moment.

Actually, the SGMA Committee, which took standardized measurements on Standard Gauge locomotives and cars to determine what optimum track spacing SGMA should use as our standard, has the overhang/underhang/height/width/etc. data on most Standard Gauge equipment but has not yet posted it on the SGMA website.  IMHO this needs to be done ASAP and I will continue to press the Committee to do just that. 

You can run and I have run straight track closer together on my SGMA modules than 7-1/2" centers.  However, if you do, you have to be extra aware of what obstructions may be in the path of your SG trains.  For example, locating classic Standard Gauge trackside signals and accessories between mainlines can be problematic even with 7-1/2" centers.  Decreasing that distance only increases the potential collision problems between train and signal/accessory.  As a general rule of thumb, the maximum witdth of Standard Gauge trains is about 5-1/2".  Therefore, don't run your"straight" mainline tracks any closer than 6" centers, which should provide about a 1/2" space between trains passing on the two adjacent mainlines.

One other clearance problem that should be mentioned is the installation of classic tinplate switches.  Their large, fixed-location, switch motor and lantern assemblies though attractive, make them impossible to install and/or use in some situations.  For example, they're too large to be used to install a crossover between mainlines on 7-1/2" centers.  In addition, some locomotives such as the new Super 381 locomotives can't pass throught the switch without coming in contact with the bulky motor/lantern assembly of the switch (why MTH/LCT didn't fix this problem when designing their Super 381 is beyond me).  Fortunately, the new Ross Standard Gauge switches with their low profile switch motors, which can be mounted on either side of the switch, solve these problems.

Bob Nelson

Not only won't a Super 381 pass through the curved leg of an MTH switch without fouling the actuator arm, it won't clear an illuminated Standard Gauge lockon. MTH product engineering appears to have been "asleep at the switch" when they let the Super 381 out the door.

Thanks everyone. I going to order some track and keep it flexible as I start to acquire more engines.

Southwest. How is the Tucson train show? Much tinplate or Standard Gauge? How many tables? I only ask because I live in So Cal.

Thanks,

Bob

Bob

The Tucson show is a good event, possibly the best in Arizona. Certainly no less than second; the TCA Desert Division show in Phoenix on Thanksgiving weekend might edge us out, especially in the tinplate category. I wouldn't drive 3-400 miles just to go to our show, but if you're contemplating a trip to Southern Arizona anyway, maybe you want to see the Desert Museum, Saguaro National Park, the Aerospace Museum, etc., it would be worth your while to schedule your trip to include the show. We get quite a few vendors from Phoenix, Southern California, and New Mexico, so it's more than just a local show. Dates are November 8-9; our museum (Gadsden Pacific Toy Train Museum) has an open house on Sunday the 10th so you could come to that too. You're welcome to bring a train and run it on the tinplate layout as my guest if you like. 

Table count is consistently over 100; I'd have to check with the show manager but I'd guess it will be about 130 for next month's show. Standard Gauge content goes up and down. Sometimes it's pretty good, sometimes it's a desert (OK, Tucson is a desert anyway). Last show I snagged a 155 freight platform in great shape with a partial off-color repaint for under a hundred bucks. I've gotten some other pretty neat stuff at the show from time to time, but Arizona isn't Pennsylvania when it comes to tinplate. 

E-mail me for more info if you like; my e-mail is in my profile. I will have four tables at the show, including some tinplate, and I do some of the publicity for it. Here are a couple of pictures of a previous show. The first shows part of the sales area with one of my tables in the foreground. The second is a couple of our guys with a portable Standard Gauge layout that is usually at the show. As far as I know it will be there this time.

-

Hi Southwest,

Sounds like a great show and my wife and I have been wanting to visit southern Arizona for a while. The spring show looks like a better fit with added doctor visits next week. I would love to visit the Toy Train Museum. I will email you in Jan for more info.

Thanks,

Bob

Throwing The Brute into the mix along with those Showroom cars on the outside,do you think that  7.5" would still work?  I might begin with at least 8.5" and go from there.

Norm