I have a lot of old (80s grey era and 90s 9v) trains. Some of the wheels squeak and many have quite a bit of friction. Sometimes this friction causes the locomotive to detach from the rollingstock since the friction of the wheels on long trains is greater than the magnetic force between the couplers.

I searched this site and the closest match I could find is: How to lubricate the 4.5v train motor for set 7722? It mentions using 'plastic safe oil' but does not specify a brand. This warning is echoed across the model train internet and some (non-Lego) discussions have recommended using a full-synthetic motor oil applied via a needle oiler.

The linked question is specific to the motor and gears that are likely to be designed to be lubricated vs wheel axles that are not. I was going to use 3in1 oil but the consensus seems to be that this is a bad idea because it is a petroleum derivative.

Does anyone have any first-hand experience of a 'plastic safe' oil that they have used on their Lego? I would think any oil would work to lubricate the axles but I want to be sure it will not damage the plastic over time.

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    Where in the world are you? I don't have any experience with this, but if I did, I might suggest a brand of oil available here in Denmark, which might not be of much use if you are far away, Commented Oct 8, 2020 at 6:28
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    @Henriksupportsthecommunity I would love to see your suggestion. Based on your knowledge of the right oil we may find derivatives in other countries and brands.
    – Alex
    Commented Oct 8, 2020 at 16:37
  • As I said I don't have any experience, so I don't have any suggestion. Commented Oct 9, 2020 at 6:48
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    As a first step I would suggest a food grade mineral oil. It's as close to non-toxic as oils get. It non-penetrating and displaces water, One typical household use is as a surface protection for wooden cutting boards and kitchen utensils,
    – Dan1138
    Commented Oct 10, 2020 at 1:26
  • I wrote the top answer on the motor lubricating question you linked. I can recommend the Fleischmann oil mentioned below. I use that as well. Marklin (another model-train brand) also has comparable oil.
    – Tonny
    Commented Oct 12, 2020 at 10:05

2 Answers 2


Generally for this sort of thing the recommendation is a "light machine oil" (the wording from the Hornby Maintenance sheets). These are "non-penetrating" and so won't damage the plastics which might happen with 3-in-1 or WD-40 style oils.

This can often be found as "Sewing Machine Oil".

Fleischmann (a model railway brand) sell their own "Special Lubricating Oil" (FM6599) for use on their and other trains, that is usually widely available, but is probably somewhat more expensive than a general purpose machine oil.

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    Thanks for the lead on sewing machine oil. Did some googling and it looks like this may be a good choice: amazon.com/dp/B00GC54OC2 Tri-Flow, Lubricant with Teflon. What do you think?
    – mcqwerty
    Commented Oct 9, 2020 at 13:56
  • I'd be wary of that one as it explicitly states "Penetrates Fastly" [sic]. You would probably be better off with amazon.com/dp/B008QNQ2VE I think. Commented Oct 9, 2020 at 17:56
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    I use the Fleischmann oil as well. Marklin (another model-train brand) has similar oil as well.
    – Tonny
    Commented Oct 12, 2020 at 10:07

Petroleum based lubricants you need to be careful with, since they can act as solvents. Zhaph mentioned non-penetrating machine oil, this sounds like a safe bet. If you are in doubt, grab a gnawed brick and submerge it in a sample for a few days and see what happens before putting it on your precious train parts. Science!

Second hand info:

I have heard that some silicone based lubricants might be really good for Lego, since they can soak in and are unlikely to react with the ABS. Might be worth a test if you are really serious about low friction/wear in your trains?

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