Put the triggering source directly below Post Office and the useful target directly above it. When that lower building triggers, Post Office relays a trigger upward, as described by emgeal’s Quick Overview. Start with a source that already fires; the Post Office does not create the first event.
Read the direction before placing
This is a directional relay, not a general “nearby buildings” bonus. The next figure expresses the author-documented relation. It is not a claim about extra lateral spaces, exact tiles or a repeat frequency.
Inverting the stack leaves the source above and target below, which is not the relation reported in the guide. A Conduit may introduce random targeting, so it should not be presented as a controlled, deterministic substitute.
Build a controlled relay in three checks
- Prove the source: identify a lower building that visibly triggers on its own or from an already working chain. emgeal mentions Way Station as one possible recurring source, subject to the card you have.
- Place the relay: leave the direct-below and direct-above positions open. Check legality and orientation in the live placement preview before committing.
- Pick the target: use an above building whose trigger has real value in this run. Watch one complete source → Post Office → target event before adding more relays or multipliers.
The source guide also discusses Lamppost and Railroad as supporting pieces, but neither proves this vertical chain by itself. Railroad changes adjacency; Post Office cares about the documented below-to-above trigger relation.
If nothing fires, locate the failed link
| Symptom | Check |
|---|---|
| No source event | Make the lower building work independently first. An inert source gives Post Office nothing to relay. |
| Source fires, target does not | Recheck direct-below and direct-above orientation, target legality and the current placement preview. |
| Effect seems delayed | Inspect cooldown or waiting conditions before rebuilding. |
| Conduit hits something else | Treat random targeting as a separate plan, not a guaranteed single-target loop. |
For a broader placement problem, use the source → position → target → cooldown guide. No source checked here supports an infinite loop or guaranteed score.
Post Office direction is attributed to emgeal’s Steam player guide, checked Sep 29, 2026. This page does not claim our own playtest or a guaranteed combo.