Minimum curve radii data, O/O27

OK, I know this is an open ended question, but here goes;

With regards to engines (any), Minimum curve radius information seems pretty hit or miss and basically hard to come by. Especially for older “no longer cataloged” items. (Ex: the GG1’s I’m longing for)

Is there a source/archive/clearinghouse for this type of information ?

I’m guessing I’ll just have to dig dig dig before I buy.

Thanks

Fred

Oh and Buckeye, if the French get Cleveland due to this whole Lionel legal mess, we can just round up a few middle school football squads and kick em out [:D]

Hi Fred,

I am not aware of a general toy train reference that would provide the minimum radius for all manufacturers equipment from all eras. My best references are to go back to the original catalogs for most modern equipment. This forum is another good source. Post the manufacturer and model number you are interested in and we (other forum members) can check our sources such as old catalogs, magazine product reviews and reference books.

Regards,

Tim Pignatari

Postwar GG1, GP7, RDC, EP5, S2, Anniversary Alco will do O27. Trainmaster, scale Hudson will not (without modification). F3 with vertical motors will, horizontal will not. I get off on making stuff run on O27 that isn’t supposed to; and I have a lot of postwar. So, if you have a question about a specific locomotive that I haven’t mentioned, I may be able to help.

This topic is a bit of a pet peeve of mine.

I run O27 profile track and 30 of my 36 switches are 27". Many curves are also 27" even though I have 42" and 54" but less of these.

I emailed both CTT and OGR and asked why in their reviews they won’t mention if a train runs on 27" curves or not - especially when the manufacturer claims 31" minimum. I have 4 MTH engines that are listed as 31" min but they easily handle 27" curves and switches (both Lionel’s and K-Line’s). I would have never bought the engines if it wasn’t for forum members telling me that they would handle 27".

I sent the email about a year ago after reading a review in CTT where they talked and/or showed the engine running on their ‘floor special’ or whatever they call it. I know that they use Lionel’s 27" switches on that layout (Lionel’s switches have large motor housing and that’s why they’re an issue). But yet the review said minimum curve 31". Go figure. To me they should tell it like it is.

Unfortunately I know of no source of this type of information either - not even if you contact the manufacturer and ask, which I’ve tried!

  • walt

Yes, Fred that would solve the problem with the French. I’m so glad you didn’t suggest the OSU Buckeyes. They can’t even make fake money. [:D]

A lionel F3 with horizontal motors runs on the minimum of maerklin, wich is 75cm. (75 divided by 2.5=30inches) so it will run on 031.
The best thing is to use 031 as minimum if possible. If you make an S-curve, use a piece of straight between it and watch that the cars u use have couplers that are not fixed solid to the boogies. If possible, a slightly bigger radius (045 before a 031 curve) can be used to guide the train into the curve, and besides that gives the visible impression that the curve is wider.
If buying on ebay, I always ask before I buy…

Fred, Walt and I are riding on the same train (Hi’ya Walt! See ya’ in the club car!) when it comes to this topic. I have talked personally with a couple train company people and the reason that they do not always openly advertise an engine’s ability to negotiate the 027 curve (and switch boxes) is simply they feel by saying this some folks (especially those into scale) will view the product as a toy.

In the case of MTH product, they do not even make 027 track. Yet they do advertise some product (in particular rolling stock) as making the 027 curves. I was told by someone at MTH that they need to test the product before they state it clears the 027 curves. But since the Railking loco line has moved into more of the “scale” arena, I’m sure the admission of clearing 027 curves relates more to not wanting to lose sales.

Notice in many recent Lionel catalogs that there are locos included in starter sets with 027 track that are then available for separate sale, but with a minimum 031 curve. Huh? If a GP-9 comes with 027 track in a train set, one can assume it does run on 027 track, whether bought in a set or separate sale.

Believe me Fred, there is a great deal of negative feeling when it comes to advertising a product’s ability to make the 027 curve. This is because many many modelers equate 027 with “toy” trains and “not scale” and simply cannot accept the fact there are modelers who CHOOSE 027 track due to either space or financial constraints.

Now, it is important to note (as Walt mentioned) that it is the switch box housing on the 027 switches (post MPC era) that is the main culprit here. I have modified and lowered the housing on the manual switches which solves this problem. Also to be noted is that K-Line’s new 027 turnout has a new very low housing. Some of the older Lionel switches like the 1024 type, will allow some other products to be run that will not clear the larger switch box housing of the MPC-era trunouts. Our friend Walt has posted some info here i

I guess its time for me to also pop in here. As Brian will recall, some of my first posting on this forum was about the K-line low profile 027 trunouts. I have them and love them. This does allow me to run many very large engines on 027 track.


K-line low profile 027 turnouts


C-O Allegheny (by MTH Railking)


C-O Allegheny and UP Challenger


Here is a K-line Trainsmaster (scale) going thru the turnouts.

I should point out that the centerline distance between the trucks and the amount of angle turning of the truck will determine what the min. dia track it can run on.

tom

Fred,
I have also had success with running Lionel deisels on 0-27 track. RS-11, Sd-80MACs, RS3 KCS, run great on my layout. I just run the 0-27 curves in an arc and break it up with a straight or half straight. My NYC Lionmaster J3a Has lots of trouble and an SP 4-4-2 Atlantic has problems too. But my Lionmaster Big Boy can handle them but I prefer to run her on 0-54 because it looks neater.
Laz57

You don’t say if you’ve built a layout yet so I’ll put in my 2 cents for what it’s worth.

Assumming tubular track, I like to keep curves to a mininum of 042 with 042 or 072 switches and maybe 027 or 031 switches for spurs. Even if it means sacraficing twists in the design or an additional mainline. Cramming as much track as you can in a layout makes things interesting but too much of a good thing can take away operating fun. Idealy, your curve diameter should be at least 3 times the length of your largest engine. Although many engines and cars will handle 027 or 031 curves, these diameters put too many limitations on running in my opinion. Unless you’re running small switch engines and 027 cars, trains look more like trolleys navigating small curves. They cause derailments, trains slow down abruptly, and top heavy steamers without magnetraction are prone to topple over at higher speeds. If you’re building a 4 x 8 layout, you can have an outside mainline of 042 with an inside mainline or branchline of 031 or 027. The design won’t have much twist to it but it pays back in better running characteristics.

I use John’s outside-mainline idea, for visiting equipment. However, I use Marx O34, which has the O27 profile and is not hard to find even though it hasn’t been made for many years.

Consider spiral curves. These combine a large radius at each end and a short radius, like O27, in the middle. Example: 22.5 degrees of O54, 45 degrees of O27, 22.5 degrees of O54. Spirals do two things for you: They look much gentler than they really are. And they allow you save space by putting the tangents leading to the curve much closer to a wall, since the ends of the cars and locomotives don’t swing very far out until they have already moved away from the wall. You will find that the center section will be about the same distance from the corner of the layout as if the whole curve had the same tight radius.

Brianel, as usual, a nice and very thorough discussion.

BTW: I don’t recall who convinced me to FINALLY start replacing my Lionel with K-Line but I have started: 12 so far (I can’t thank that person enough for giving me that one last pu***o get me over the indecision hump). No more switch chattering problem and and no more concerns about the housing.

As a side note on the Lionel switch motor housing: I have numerous MTH RK box cars and reefers than negotiate the switch motor housing but it’s tricky: the car sides are JUST HIGH ENOUGH that they go OVER the housing!. If they sat lower they would not clear. In fact, I bought the MTH RK Heinz striped Pickle car and its sides sit maybe 1/8" lower and it won’t clear the housing - even though the car has the same exact dimensions as the 35 other RK reefers/box cars that I have.

I have several older RK tankers and they are all fine too.

Also, I know that length doesn’t matter when it comes to cars (careful now!!!). I bought a K-Line PRR caboose and it’s trucks would not swing enough to go around 27" curves. Had to take it back.

I can only chime in with these engines. They do handle Lionel’s housing OK:

  • MTH RK PRR 6-8-6 baby turbine (PS2 version).
  • MTH RK SW1500 switchers (PS2 version).
  • MTH RK F3s (SF and NYC) but these are 4 to 5 years old. (PS1 version)

As alluded to above, we’re going to have to start being careful when referring to Railking. We’re going to have to start saying “older RK” or “newer RK”. I would bet that the newer RK F3s won’t handle Lionel switch housing.

  • Walt

You say that like it’s a bad thing [;)]

Face it everyone: if it ain’t 1:1 sacle AND making money, it’s a TOY. . . . [}:)]

[quote]
Originally posted by brianel027

I have talked personally with a couple train company people and the reason that they do not always openly advertise an engine’s ability to negotiate the 027 curve (and switch boxes) is simply they feel by saying this some folks (especially those into scale) will view the product as a toy.[/br]

Thanks a ton to everybody who posted here. Fantastic info.

My resurrection of the family heirlooms (in time for Christmas) is turning into something of a semi-permanent setup me thinks.

I’ve gone to 042 for the mainline and 027 for the turnouts along with a bunch of half straight and curves to get three turnouts inside a 66" x 44" layout.

So Far . . . . . .

Just in case this thread this continues and acts as an unofficial source of equipment that can handle O27 curves (maybe we should start another thread and try to keep it active and updatable??) I left one engine off of my list:

MTH RK Erie Lackawanna RS3 (PS2 version) handles both O27 and Lionel switches.

  • walt

I just wanted to say, of my approx 30 some engines that I have, Lionel, MTH and K-line, they all run on my 027 layout. You can check my web page (click on the icon below) and see them.

tom

Spanky, I wanted to say I like your photos. One of these days the economy will turn around for me and I can lay my hands on a digital camera. My layout isn’t big, but I run a lot of stuff that totally unique to my layout - at least for the scale of the stuff.

Now Walt, I think between you and I (if you decide to hang out here a little more) we could keep this thread going. After all, I ain’t “Agent Atlas 0.”

I am “Agent 027.” [8]

I just gotta watch out for that Baron Scalenstein. Last time he visited, I ened up being chased away from YORK by a angry mob of prototype-only modelers carrying flaming torches, pitch forks and screaming something about burning the 027 monster at the stake. [:D]

Thanks Brian,

My wife gave me this camera last year, and it has provided me with the greatest play value of all. The best $150.00 she spent.

tom

Brianel:

You said “if you decide to hang out here a little more” - I actually check in every day. Rarely do I contribute though since usually I don’t feel like I have the expertise to do so. I can offer opinions since everyone is entitled to one of those :slight_smile: but ‘facts’ are another matter!

Even over at OGR most of my efforts are on the Protosounds/DCS forum since it’s 95% DCS and I have DCS.

I don’t think I can help keeping this thread going since that’s all of the engines that I own! Sadly I have nothing more to contribute. Boo-hoo.

thanks - walt