It would have been good if you had used those very words the first time. They are well written and clear. Unfortunately, your earlier attempt was not. What with “mathmatics”, “Einstein”, “toast”, it was a bit meandering.
You make a good point by bringing in prototype practice, and that it might vary. I think this was discussed recently in another topic. I think the main concern here is on the layout level, however: Crashing trains and room for fingers and such.
I am glad we provide levity for you. I am sure you provide levity for some of us, and I hope that pleases you, also.
I guess I thought with the exception of the only serious posts that addressed the topic correctly…you and Kevin basically saying that “it depends” , that the bulk of the thread was unserious, semi scarcastic banter.
I thought that theoretical discussions about preplanning the precision needed to lay track similar to engineers building a 747 was actually a big joke…like the Toast thread and the five page discussion on torquing a screw into plywood years ago.
My apologies for misunderstanding if folks were being serious.
BTW, an NMRA gauge? I’ve been in the hobby 40 years and built three layouts (yes, successfully) and I never could figure out what I would use it for.
Still having fun, with no derailments, mysteriously uncoupling cars, or shorts occuring on Peco turnouts.
Not sure where Kevin fits in here. I was agreeing with Ed that the OP should test the track for clearance, and I made that same argument earlier in the thread, the very first reply in fact. I was being totally serious. I am a big believer in mathematics, but I also respect empirical evidence. When you are dealing with clearance on curves, test it.
Anyhow, all’s well that ends well.
Rich
P.S. It looks like you edited your last reply after I posted mine. The reference to engineers building a 747 totally baffles me. Are you confusing this thread with some other thread?
Kevin offered his advice based on experience. I thought that the advice that was based upon arguing the possible mathmatical solutions in the planning stages were less than sincere about answering the OPs question and more about something else…what I’m not sure.
If you take your advice about testing various combinations, and go through several iterations, you could lay two pieces of track, have it work for 40 years, and never ever know what the exact spacing between centers was.
The only reason you would have to measure it…at all in 40 years… is if you were going to lay another track in exactly the same yard where the exact same equipment would run…where no vehicles would be passing…where no maintenance shed would be located. Change one variable, and the spacing required changes too. And, you wouldn’t even need to measure it if you simply eyeballed it and had enough space to work with to account for being 3/32nds off on a few tracks.
I guess I get frustrated when answers are given that imply its “only the engeering way or the hiway” when it comes to layout building.
Well, here is my reply to the OP, verbatim, and it was the first reply to this thread.
It was a serious reply based upon my own experience.
After I posted that reply to the OP, my subsequent replies were in support of Crandell’s and Ed’s similar responses - - - test the trackwork to see if it creates clearance problems or not.
Mathematics can be quite useful in our field. For example, if you have a room 12 feet wide and you want layout 4 feet wide on each side, I can tell you the aisle width without having to lay out and measure a real room. Or even measuring off of a scale drawing.
My calculations were a slight step above that operation.
I suggested building a test setup because of the “trust but verify” concept. Plus, with our models, there can be an amazing amount of slop in mechanical dimensions, especially in trackwork.
Also, the layout builder might find that, although the clearances are what I predicted; in real life, those clearances are still too small for his tastes (sorta how they must do airplane seating).
Here’s a thought: if 2" track centres on tight radius curves can’t work why does Atlas make sectional track in 22" and 24" radii? I note the absence of 20" radius sectional curves but 15" and 18" are made.
Doesn’t Kato make sectional curves in 2" increments?
I think the post was about not really caring how wide the aisle actually is as long as it is wide enough.
And manned flight was discovered empirically, just by the way. Nobody knew any of the required mathematics until flight was achieved.
One of the great engineering ironies is sailing craft were only precisely understood after manned flight was precisely understood. Man had been sailing successfully for thousands of years before we actually understood how it works.
In the very short time since of course man has flown faster than the speed of sound (the aerodynamics are totally different) and sailboats now routinely exceed the speed of the wind by a factor of three or more.
Man got exactly nowhere with just a slide rule. Empirically, we circled the globe…
Anybody care to guess what this track spacing would scale down to in terms of inches on center? Keeping in mind that its likely designed for a fairly uniform type of car. (Hoping the watermark printing satisfies copyright requirements).
Or this?
Or the yard that has access down the middle?
Hard to tell…
Do all the tracks in a yard even have the same center spacing?
I’m not guessing. I’m using that mathematics thing, again:
I can’t tell the track spacing on the other two, but the one above is about 12’ -6", or 1 3/4" in HO. I guess they’re not followers of Inch-and-a-half Mike.
The curves are clearly hugely wider than what we use, and I doubt there’d be a need to increase track centers if it were reproduced in HO.
If you’re advocating such a spacing in HO, it does make sense if you don’t feel the need to reach in and pick up or rerail a car.
If I had the room, and I were building a staging yard, I would want 2 1/2" to 3", for easy finger clearance. Most people, probably including me, would likely shrink that number for more tracks. Remember, staging can include adding and removing cars.
I’ll mention that, in the real world, I worked on a project that had a 3" clearance between train and (large) obstruction.
Since I am in the planning phase, I’m going to just go to a 2-1/2 inch track spacing throughout my HO switching layout. My four axle diesels and 60 ft cars should not have any problems “interacting” with cars/locos on adjacent straight or curved track. Much easier to plan with software using a common spacing and will fit easily on the planned benchwork. Yard will only have five tracks and in the switching area, max of two through tracks plus sidings.
Sorry, having implicit understanding of that math thing, I know that an answer is not mathematically precise once the inputs start with the word “about”.
Since the math thing only really finds a precise answer when all of the inputs are constant knowns, the only math that matters here is when you plug your guess into the formula that scales your guess down to an HO relevant guess.
I’m not going to argue, dispute, suggest or disagree with anything or anybody here.
I’m just going to make three simple statements.
First, as orginally suggested by several/many so far, simple testing is always a good idea.
Second, the NMRA has always been very “generous”, and thereby conservative in its recomendations for curved track centers. Yet they have always “danced around” the tangent track center issue with scale feet rather than a real life dimension.
Their 14 scale foot recommendation is 1.931"…
Third, I have used 2" track centers for tangent track since I was introduced to this hobby. As explained earlier it is the defacto industry standard for bridges, crossovers, etc.
I have used 2" track centers on curves, maybe sometimes stretching them out to 2-1/8", ever since I started using 36" radius as my minimum.
I have tested this with locos as big as the Bachmann EM-1 passing 80’ Bachmann and Branchline passenger cars with no issues and room to spare.
So for appearance, space and better track civil engineering (yes, I engineer the track location before I install it), I will stay with 2" (or cheat them up just that 1/8") track centers. The NMRA recommended 2-15/32&
IF you might be running articulateds that don’t swivel the “rear” engine, you do need to be careful about curve spacing where they run.
I mentioned the Big Boy earlier, that has a half inch overhang on a 37" curve. And that’s the theoretical (mathematics again at work, here). YOUR model might be more.
But it’s not just Big Boy’s. There are other big articulateds that come mighty close.
And, lest you think that the above comment only applies to those darn brass locos, I remind you that the Intermountain Cab Forward does not have a swivel “rear” engine.
Maybe someone will make another plastic non-swivel articulated someday. Maybe.
