Everything on model trains, model railroads, model railways, locomotives, model train layouts, scenery, wiring, DCC and more. Enjoy the world's best hobby... model railroading!

15 scale models background city buildings

HO and OO Compatibility

Maria asks:

“Is it feasible to connect an OO gauge turnout to an HO track made by the same manufacturer?”

You can add your comment below.

10 Responses to HO and OO Compatibility

  • Morgan BIlbo says:

    The answer should be obvious. NO. HO is 3.5mm to a foot, OO is 4mm to a foot. Track is 4’8.5″. So figure that out and it becomes obvious.

    • David Stokes says:

      Sorry, no cigar Morgan.

      The track gauges in 00 and H0 are both 16.5mm.
      The difference is in the size of rollingstock and locos. 00 are 10% approximately bigger than H0.

  • Frank Yost says:

    Just try it. The rail height, (code), may be different. Experimenting is part of the hobby. Have fun!

  • geoff says:

    The answer is yes, despite what Morgan says, since OO and HO have the same gauge 16.5 mm. But you need to make sure the rail code (eg 80 etc) is the same. You also might need to adjust the track height.

    Although OO and HO have different scales, OO is 1/76, HO is 1/87, for historical reasons OO uses the same track gauge as HO. That’s why quite a few people who model in OO, or 1/76 use EM gauge, which has track and models gauged for 18 mm, which is the more accurate 1/76 for 4ft 8.5 inches.

    One thing that the different scale means is that the sleeper / tie spacing will be and look different. And the scenic fixtures, if any, on the turntable will be slightly larger than similar HO fixtures elsewhere on the layout. The clearance should be ok. OO models are slightly larger, but HO prototypes are usually slightly larger than those OO models are based on.

    • Mark J says:

      Agree with everything but the last sentence. Both scales use the same track, but OO models are larger than their HO counterparts. A 76ft coach would be 1 foot long in OO (1ft=76ft) but would be less than 1 foot in HO since 1ft=87ft.

      • Geoff says:

        I should have been more precise! I should have said that “the prototypes that HO models are based on are slightly larger than the prototypes for OO models, given that OO models are usually of british railways and HO are usually of continental or north american railways”.

  • Nigel says:

    In general, track sold as OO scale is, in fact HO. This is certainly the case for the two main UK manufacturers – Hornby and Peco so the answer to your question is almost certainly yes. Peco do produce a range of OO scale track which has the correct sleeper spacing for 4mm to the foot but the same 16.5mm gauge as HO – the main connectivity challenge between this and other track is the rail profile (this is bullhead, most other track is flat bottom rail) and ‘code’ (height of the rail in one thousandths of an inch – however, there are usually special track pieces available to facilitate this.

    Take a look at the Peco website and you’ll see their main range of ‘Streamline’ track described as OO/HO because it’s suitable for running trains of both scales, albeit with sleeper spacing and gauge compromises for OO.

    I hope this helps.

  • Joseph Bonadies says:

    Yes, I run both scale locos and wagons, 00 scale and HO, on a HO Hornby track, with out any problems,
    there is a small difference, with the size of the rolling stock , 00 scale is British and little Larger than the European HO scale.

  • Morgan BIlbo says:

    Wow! Of course, I was wrong. I’m in the US. OO and HO are ? UK or European. I didn’t know they had the same gauge. I gave the scale. Most of what others said is correct.

    • Frank B says:

       USA and continental = HO = 1/87, UK = OO += 1/76, but both run on the same 16.5mm track. This was because historically, British railways were built with a smaller loading gauge, therefore the motors for American HO locos would not fit in a British HO loco, so the scale had to be enlarged to OO to match the available motors.

Leave a Reply

Your email address will not be published. Required fields are marked *

Add a photo or image related to your comment (JPEG only)

Use Tiny Railroad Micro Controllers

N Scale Track Plans

Watch Video

Download Your Free Catalog

Model Train DCC HELP


Model Train Help Ebook


FREE Tour Inside Club

Take a FREE tour inside the club.

Scenery Techniques Explained

Scenery & Layout Ideas

Model Railroading Blog Archive

Reader Poll

Sorry, there are no polls available at the moment.