I work at a small company in the railway industry. In our office, there's a model railroad that's sometimes used as an eycatcher in the company's stall at trade shows. It isn't landscaped, so any addition is bound to be spotted, sooner or later.
One Christmas, I added a Christmas tree for fun, eventually exchanging it for other items.
I used a brush-type tree that I cut to size, covered with glue and dipped in pine-needle-like fibres (landscaping supplies).
The snowman's right arm is a signalling staff used by station masters at the Swedish railways in the past. One end has a red flag for signalling 'stop', wrapped around the staff when not in use.
When it started thawing, the snowman got sad, and had trouble keeping his balance.
When Spring arrived, there wasn't much left of him, just his hat, signalling staff (the flag now partially unfurled), and carrot nose, all sitting in a puddle of water among the crocuses.
The snowmen are made of Fimo clay, with Liquid Fimo for water and melting snow. The rest is metal wire, paint, and ground foam for landscaping.
The station master has been sitting in the lilac bower, enjoying a warm Spring day. He's gone to fetch a cup of coffee, leaving his hat and signalling staff behind.
I made the sofa and table top from fine metal net. The settee legs are made of metal wire and the table base of metal findings.