You can use either keyword search- example "Hogwarts" or specific locomotive or set product numbers- example 6-38xxx for an engine.
Lionel mostly used inch sizing in designations or descriptions of tires. MTH went metric. You can buy a cheap set of digital calipers and measure wheel diameters and use the MTH system since they give a range of wheel diameter- certain size of tire. https://mthtrains.com/sites/de...HART_REVISED_ALL.pdf There are a number of folks like myself that often use the MTH tires on other brands because the numbering and sizing is relatively easy. That said, it does not work for everything and there are some engines and wheels that have different traction tire widths or thickness that make an MTH tire incompatible or just lesser suited.
With Lionel, you have to do the product number system and then chase down alternates. One good thing on the Lionel side, there is the half off parts sale coming up September 23rd-25th http://www.lionel.com/articles...ual-Parts-Sale-2022/
Yes, with keyword search, you need a little background knowledge. Example, on Hogwarts, they made several different versions, but for the handrail stanchions they to my knowledge used the same basic boiler shell over and over and over. https://www.lionelsupport.com/...101069001?quantity=1
They don't break out the stanchions in the diagram but list the 2 different color ones
For the record, again, this is my annoyance with the Lionel system, traction tires were linked by locomotive product number, and then that part number gets deprecated. So then you have to search by decimal inch or fraction sizing.
So then we get this as the now current available tire in that size.
https://www.lionelsupport.com/...-x-.056-TH-x-.142-WD
Also, this where knowing that certain engines- example the Hogwarts style Victorian engine series, used big and thick very specific tires that could not be substituted easily from other brands. Again, it's these larger driver wheels with deep groove for the traction tire, and the width, thickness and diameter was not used by MTH as an example.
Sorry, I wish there was some easy answer but there isn't. Hopefully I've given you some tips and yes, the Lionel system will have you searching for alternates most likely for at least one engine.