To be honest, plastic modellers on the whole are ahead of railway modellers when it comes to painting and effects, and please, no one take offence, but overall I think they are. The techniques, tools and materials are far in advanced from what we use and due to our insular? hobby we tend (as a whole) not to look elsewhere for inspiration and ideas, which is a great shame as there's a lot to learn out there, as already noted above.
I personally think it's down to the medium of the model, static models need something extra to give them zing and make them special, model trains are already several steps in front because they 'move' which is their added bonus, it can also be their downfall as they require a certain amount of durability that often prohibits the minute and sometimes fragile detail static modellers can incorporate.
To be fair, some model railway builders are now using techniques such as dry brushing on highlights and worn areas and forced shadows to darken recesses, several show case their models here, so some of the techniques are beginning to filter through and it can only get better
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