Smallest radius for HO scale?

Model Railroader Layouts and layout building
41

I have to agree with Phoebe Vet about “minimum” radius. Having done it myself, I can assure you that all my equipment WILL run on 22" diameter curves, and I have some long 6 axle diesels and 85’ passenger cars. Now, is that ideal, from both an operational and appearance perspective? Probably not – that would be closer to the 1:2.5 or 1:3 ratios suggested by Paul. But, given the space constraints or my layout area, I have two choices, give up the longer equipment, or tolerate the substandard appearance. I chose the latter.

And in response to one of the OP’s questions above, yes, I have my loco maintenance area inside one of the return loops at the ends of my layout. Again, the design might not please a purist, but it works for me, maximizing the use of available space.

42

I made a partial response to this above, but to keep the turnout size up (min #6), I came off of the leg well up from the loop. Here is an older view of my plan, but it illustrates the concept.

43

It is not totally clear what the OP means by “themed trains”. He says he likes themes, for example, “a military theme, or beer train theme that I could center around a brewery building, etc.”.

As Phoebe Vet says, that could mean anything from industry specific unit trains to Coors Silver Bullet trains.

The OP ought to elaborate and give some specific examples of train sets that he likes and might possibly acquire that are “themed”.

Rich

44

Pike Stuff (if I remembver correctly) makes one and two bay modern style maintenence bays or engine houses. They are made to look like they have aluminum siding. I have the two bay as seen below from Rix/Pikestuff:

http://www.rixproducts.com/enginehouse_1_or_2_door.htm

They have a lot of “modern” buildings that would work for 1970’s and 1980’s to the present in N and HO. They have a cars shop and many other buildings suitable you should like.

As for radius, I’ve done a fair amount of track design and suggest John Armstrongs “Track Planning for Realistic Operation”. That has been one of the track planning “bibles” for years and while it doesn’t off much in therms of 101 track plans, it gives you the tools and understanding how to design a track plan and fit it in a small space and get the most out ofi t.

If you are going to go with HO, I’d personally suggest squeezing in the biggest radius possible above 22 -inches. 22-inches is a “train set” snap track standard radius meant to fit a 4x8 sheet of plywood, but if you use flex track you can up your radii a little and still keep it within the confines of your space.

Every little bit makes a big difference at that size, so if you can manage 24 or 26 inches, it will reap benefits later on when you see some longer freight or passinger cars you just wish you could run, and since you designed a decent minimum radius, in most cases you will be glad you did later on. 1971-present = more and more longer cars and engines, even if you pick and choose what you like, chances are some will be long! I couldn’t resist those 1970’s Vert-a-pac cars from ExactRail and t

45

First by themed trains I mean like the Coors Silver Bullet train and trains that haul nothing but coal on its way to a coal fired power plant, this would be industry specific.

Second, I appreciated the advice but get the feeling Paul is being a bit arrogant here. That I can do without. I am open to suggestions on read material, but prefere to do so from an free online source, not a hard copy book. Are there any online resources that will provide the info. I am looking for. A simple yes, with a link will suffice, or a simple no, if not.

Third, I have no intention of being a purist. I also get the feeling Paul is one and is maybe looking down his nose at a newbie here, in this case me, who is not going to be a purist. Again, this I can do without.

46

SUX V R40 Rider,

Paul is really a very helpful guy, but sometimes a little impatient. By no means he is arrogant, just a little rough at times - like so many Dutchmen.

His advice is most valuable and it pays off to listen to him.

47

SUX:

Please don’t interpret the fact that Paul and I disagreed on a relatively minor point as a critique of Paul’s skill or knowledge. He was telling you what is ideal. I was telling you what is possible. This forum represents many points of view. We each express our own. It is not personal.

From each post take what is helpful to you and disregard the rest. You can learn much from many different people, including Paul. You will never agree with everyone.

48

hi,

i gave two arguments why having a 22 " radius for HO trains might be not such a good idea when wall to wall space is just 4 feet. Tight radii in combination with pushing long cuts of cars when switching, especially with consists of mixed length, are prone to derailments. Leaving a bit more space then one inch between the tracks and the walls would lead to radii less then 22". Some space is needed for the background and probably for braces to support the background as well. It would not surprise me if a radius of about 18" would be chosen. Take one inch for the background and its support, 4 inches for scenery between the background and the track center-line and a 19 inch radius will be the result. So the discussion should not be focused on, if the OP could run all of his trains over a 22" radius. But on if they will run well on tighter radii and are still looking good enough. To the taste of the OP of course.

IMHO the OP has some design choices to make: more complicated then you might think. When keeping his turn-back curve some distance away from the 4 feet wide part he could have a larger minimum radius. But is the part behind the turn-back curve still accessible or should it be considered as lost? Anyway what should he do? Stick to HO and probably has to face some restrictions in choosing equipment or/and his trackplan or go for N-scale. Since i do not know the “themed trains” exactly, he spoke about passenger trains and going rather modern as well, and i do not know either about how he want to operate his trains, giving advice is difficult. Is switching, read pushing, only done from the straight or is the tight radius turn-back curve involved? Does he also wants a passing siding, with an ever smaller radius, inside the turn-back curve? We know nothing about the length of his trains nor the consists. How to advice?

You might study this: http://www.nmra.org/standards/sandrp/rp-11.html

BT

49

[quote user=“Paulus Jas”]

hi,

i gave two arguments why having a 22 " radius for HO trains might be not such a good idea when wall to wall space is just 4 feet. Tight radii in combination with pushing long cuts of cars when switching, especially with consists of mixed length, are prone to derailments. Leaving a bit more space then one inch between the tracks and the walls would lead to radii less then 22". Some space is needed for the background and probably for braces to support the background as well. It would not surprise me if a radius of about 18" would be chosen. Take one inch for the background and its support, 4 inches for scenery between the background and the track center-line and a 19 inch radius will be the result. So the discussion should not be focused on, if the OP could run all of his trains over a 22" radius. But on if they will run well on tighter radii and are still looking good enough. To the taste of the OP of course.

IMHO the OP has some design choices to make: more complicated then you might think. When keeping his turn-back curve some distance away from the 4 feet wide part he could have a larger minimum radius. But is the part behind the turn-back curve still accessible or should it be considered as lost? Anyway what should he do? Stick to HO and probably has to face some restrictions in choosing equipment or/and his trackplan or go for N-scale. Since i do not know the “themed trains” exactly, he spoke about passenger trains and going rather modern as well, and i do not know either about how he want to operate his trains, giving advice is difficult. Is switching, read pushing, only done from the straight or is the tight radius turn-back curve involved? Does he also wants a passing siding, with an ever smaller radius, inside the turn-back curve? We know nothing about the length of his trains nor the consists. How to advice?

You might study this: http://www.nmra.org/stan

50

hi Sux,

on a more personal note, i have pretty strong opinions about reading books. A well respected and knowledge author can describe in detail why and when certain choices have to be made. Information from the web is often haphazardly gathered and seldom compared with other options. Also on here lot of responses are from the “i like it so it is good” kind. It is impossible to give in-depth information in just a few pages. Studying a book like Track Planning For Realistic Operation by the late John Armstrong still is a must. Not only cause he describes how real railroads operate, but also because he describes the planning and design choises every model railroader has to make. The ratio’s I mentioned are just rules of thumb, still they give an idea about the prefered radii.

IMHO building a rather large layout first and being confronted with short-comings later is rather frustrating.

Modern freight cars and coaches are between 70 and 90 feet long. This is far away from the 35 to 50 feet cars from the 50’s. Tight radii like18" were already called tight in the past and considered suited for branchlines only, when these were the only cars in service. When going modern a different set of standards should be used, the ratio’s are still the same. Of course anyone has to take his own decisions and has to set his own standards.

I understand from your last posting your aim is having a pretty large “staging” yard, out in the open, where all the trains you like are parked. Operating these trains one by one merely, but having an appropriate purpose, like a passenger station, or a powerhouse for a coal train. When going to N-scale a lot more is possible. Like classification and engine service as is done in larger yards. Before you know it you’ll need a crew to operate your layout and it will take many many years to come close to completion. At least having a phase-one that can be done in a year or so would be nice.

Paul

51

Please allow me to piggy back, and to hopefully reinforce, on what Paul is attempting to impart to you:

There is a number of critical errors that virtually all of us make, and about which we rue and gnash our teeth later, often posting about our lamentably late discoveries here, ending with a [banghead] or a [:(]

You are covering the first nicely…getting good informationa and advice so that you can plan something useful and fun.

The second is not planning enough variety in the layout. It is intuitively simple and acceptable that a simple oval is going to be boring soon enough, but the fact is that so is the next order of complexity. Whether it is a figure 8 with a central crossing, or an oval with one or two sidings or passing sidings…what I mean is, real railroads don’t exist so that boys can be boys. They exist to generate a return on investment, to pay wages, to generate repair, maintenance, and recap costs, and so on. So, what most of us discover partway through playing with our first kick at the cat, so-to-speak, is that just running trains, back and forth, or around and around, gets old. You will find yourself wanting to do some switching, or maybe run a just-used engine into servicing.

The more constrained your space, and the more ambitious and detailed your installations to keep from getting bored quickly, the more constrained will your curves and turnouts necessarily be. At some point, you realize, and accept, that maybe you need to do a major rethink…either of your druthers or your configuration, but often even of the scale of choice.

Paul is saying that if your physical constraints are considerable and largely fixed, and if you want all the fun you can wring out of that space due to some pre-planned variety in what you can do with the trains/locomotives, then maybe you should be looking seriously at down-sizing to N scale. It will solve a lot of your problems instantly. It presents other proble

52

Paul, thanks again.

As an adult learner I tend to learn by doing than reading. Even if it means making mistakes and dealing with it in the process. This could be because I am a 40 year old American male and perhaps between you and I there is a generational gap and/or perhaps because we live in 2 differant countries. I have not been able to check out the link you provide yet, but will do so tonight.

I do have an excellent resource at my disposal that is also helping me. A good friend of mine, the one who re-introduced me to model railroading. I will also give him a call as well and ask his advise.

I am starting to lean more and more to N scale. I do have some questions about it though.

As I mentioned I want to set up a theme and industry specific layout with trains and buildings that symbolize a passenger depot, coal train delivering to a power plant, grain train going to a Co-Op, even fuel tankers going to or from a oil refinery or storage depot. I ahve no doubt I will find what I am looking for in N scale if that is my final decision. But I also want to find what I call fun trains like the Coor Silver Bullet train as an example. Are trains like these and other advertising and brand specific train sets available in N scale? Or are they strictly in HO scale?

53

From the outset of this thread, I have favored N scale as the approach that you should consider.

I model in HO scale, and I have a fairly large layout.

A lot of neat things can be accomplished in HO scale on relatively small layouts, but when you are fairly restricted in terms of the size of the space for your layout, and you have concerns about tight radii on the curves, it just seems that N scale should be given serious consideration as a preferred alternative. It just gives you so many more options and so much more flexibility.

Rich

54

One is probably better off if one reduces the radius about half an inch so that a transition curve can be added about one car length before and after the point where a non-transitioned curve would start.

55

I am still considering my options between N and HO scales.

If I go with HO the space for the turn around loop at the end of the run will have to be 5’ to accommodate the 22" to 34 radius that will be needed. I also may be able to put a small yard there.

The deciding factor will be how much length I will need to park each consist in the large yard where the reverse or balloon loop will be. I will use my current HO scale Hy-Vee train set as a guide for that length.I’ll simply put the train together, measure the length and add at least 6" on each end.

If I do not like how much space this will actually take I’ll go with N scale.

Of course if anyone else has a better idea on how to do this I am open to suggestions.

56

The train is 4’ long. With the over all size of the 8’ x 8’ space for the reverse loop with a yard in the middle of it I do not think this leaves enough space for what I would like to do in HO scale. Which is include a car and engine repair shop/maintenance buildings, yard office and enough track to park an entire consist. For example the Hy-Vee Savings Express, or a coal train, grain train, even an Amtrak passenger train.

Does anyone else agree?

57

SUX, you seem to talk in riddles.

thought yesterday the end of your layout was 4 feet wide, now it is 8 feet, hence this drawings for HO; If i understood your dimensions well. On the other side of your room you’ll have the space to walk along the return-curve.

A 4 feet long train probably has just 3 or 4 coaches, since your layout is rather long this is a very short train. When you are talking about 30+ radii as well, you will need a much larger space, but also the "not access " part will become much larger. When the return curve is a bit hidden it will still be looking good in spite of a smaller radius. If the staging tracks are behind the car / engine repair shop you will have hidden or concealed most of the return-curve.

Freight trains are usually longer then passenger trains, 6 or 7 feet?

Please start talking with exact drawings, often more revealing then a 1000 words.

Paul

58

I don’t know about riddles, but the OP is clearly struggling with the size of his eventual layout.

He started out by identifying an 8 x 12 space, then reduced it to 8 x 10, then 4 x 8, then back to 8 x 10, then 8 feet on one end and 4 feet on the other end, then 5 feet wide, now 8 x 8.

He is going to have to settle in on the size of his eventual layout, then decide on a scale, HO or N, then design the track plan.

Rich

59

Ok to clear up the question of the space I have for the layout here it is:

Entire Length: 27’

At one end the width is: 8’. This section will also be 8’ long. This is for the yard and reverse loop.

At the other end a max. width of: 5’. This section will also be 5’ long to accomodate HO scale with 22" or 24" radius.

In between the 8’ and 5’ sections the max. width is: 4’. This section will be 14’ long.

With 5’ on one end and 8’ on the other the radius needed for HO scale is no longer an issue. The issue now is how many trains can I park in the large yard that will be in the 8’ x 8’ section with a yard office, and at least 2 maintenance buildings. With one consist already being 4’. Another issue is the required length of the sidings on an HO train this long will need to be able to pull completely off of the mainline when it pulls up to the warehouse building.

60

How many trains can you park in a rather large yard? Assuming HO scale, you will get about 2-40’ cars onto every foot of track. Obviously as the 40’ increases to say, 60’, you park 2 cars onto every 17" of track. Add in the length of your locomotives and cabooses and you should be able to figure out how many cars you can store. But make sure that you do NOT include any track between turnout switches etc. I also urge you to listen to Paulus, and the rest. Stein, if he weighs in also has great advice. I derfer to the rest on this thread for answers to your other questions.