HO pillars - piliers Additional parts
HO train bridge pillars - piliers de ponts
New multiple parts, nouvelles pièces multiples
For the base parts, refer to: (preferably use V2 parts)
https://www.thingiverse.com/thing:6406070
For the bridge:
https://www.thingiverse.com/thing:5544184
The parts work well for the N scale (54% reduction factor in your slicer software)