# Station Master — Mainline Deck

**Describes the game as built at v0.8.0.17** (2026-09-21). These references are kept current with
every release rather than versioned as editions, so there is no version in the filename: this file
is always the latest, and the build it describes is stated here.

**Scope:** the tarot-sized Mainline cards placed between Offices — how the deck is dealt, what a
card does to a train crossing it, and the Home Deck cards played onto one.

> **Per-card numbers live in [`rules/as-built.md`](rules/as-built.md)**, which is GENERATED from
> `src/engine/content.ts` and checked by `test/card-reference.test.ts`, so it cannot disagree with
> the game. This document explains how the deck is used; that one is the table of record. Where the
> two ever differ, as-built is right.

## How Mainline cards work

At setup the game lays one Mainline card between each neighbouring pair of Offices and one beyond
each end Office, between it and a Division Point — so a game with *N* players uses **N + 1** cards.
They are **dealt from a finite deck without replacement** (since v0.6.2), so no Division can hold
two of a card printed once. The two Division Points are the fixed ends of the Division and are not
in the deck: `buildDivision` lays them itself.

A card does not belong to either neighbouring Office. It is shared Division.

### Crossing time is REGIONS, not mph

A card is divided into **regions**, and a train advances **one region per Stage**. Crossing time is
therefore `regions − startRegion`, and nothing else. **The printed mph is scenery.**

This is the part most likely to be remembered wrong, because it used to work the other way: mph set
the cost and a Slow train added a Stage to *every* card. It does not. Four things move a train's
start region and nothing else does:

1. **The card's own back region.** The Uncontrolled Siding and the Interchange print a back region
   that is not part of the road, so a train running through begins past it.
2. **A card that prints a Fast and a Slow start — and only Hilly does.** A fast train starts one
   region along and crosses in 1 Stage; a slow one takes 2. **No other card reads a train's
   Fast/Slow rating at all.**
3. **The permanent Heavy Grade modifiers**, each moving a train one region up the hill.
4. **Occupancy**: arriving to find the card occupied can put a train in the siding, a region behind.

No crossing ever takes less than one Stage.

### Traffic

Only **Double Track** lets two trains stand on one card, so a following train is not held behind a
slower one. Every other card holds one train at a time. The **Uncontrolled Siding** is not a passing
card: arriving to find a train already there puts you in the siding a region behind it — you do not
run into it, and it costs you the extra Stage instead.

Whether a following train may enter an occupied card at all is the Superintendent's ruling (§8.1,
Rules §4.5). Getting it wrong is what causes collisions.

## The deck

Ten drawable cards — Plains twice, the other eight once each — plus the two Division Point cards,
which are not drawn.

| Card | Copies |
| --- | ---: |
| Plains | 2 |
| Curves | 1 |
| Hilly | 1 |
| Heavy Grade | 1 |
| Double Track | 1 |
| Uncontrolled Siding | 1 |
| Tunnel | 1 |
| Trestle | 1 |
| Interchange | 1 |
| East / West Division Point | 1 each, not dealt |

The PDF art labels the Interchange "Yard". This reference uses **Interchange** throughout, to keep
it apart from the Division Yard, the Classification Yard, the Yard Office and the Small Yard — five
different things.

**Region counts and entry points per card are in [`rules/as-built.md`](rules/as-built.md).**

## The Interchange, and what it does NOT do

The Interchange prints a car-sorting capability. **It is not implemented, and never has been.** The
one thing the card's `sortsCars` flag actually gates is that an **Extra Train may be made up and
started here** — it is the Mainline card with a yard, which is why §7 allows it (v0.6.2). An Extra
starting here begins in the back region and takes the extra Stage.

Re-ordering a consist is done at a **Small Yard** in an Office Area, for one switching Move. See
Rules §4.3.

> **Corrected 2026-09-20.** Until this pass the card said "Cars may be sorted into any new order
> here" — on the board, in the tooltip a player reads, and in the generated reference. A card
> advertising an action the game will not offer sends a player hunting for a button that does not
> exist. The description now says what the card does.

## Heavy Grade modifiers

Home Office cards, played onto a Mainline card during a player's Draw option.

| Card | Placement and effect |
| --- | --- |
| Brakeman | Heavy Grade only. A **downhill** train starts one region further on. |
| Airbrakes | Heavy Grade only, and **Brakeman must already be on that card**. A downhill train starts one region further again. |
| Helpers | Heavy Grade only. An **uphill** train starts one region further on. |
| Realignment | Only onto an **unoccupied** Mainline card. Plains → Double Track, Curves → Plains, Uncontrolled Siding → Double Track, Trestle → Uncontrolled Siding. No other card may be realigned. |

A Heavy Grade is 3 regions, so it is 3 Stages to climb and 3 to run down before help. Modifiers
never reduce a crossing below one Stage.

### ABS Signals — an Enhancement, but it lives out here

**ABS Signals is dealt from the Home Office deck as an Enhancement, and it is the one Enhancement
that is not played into a district.** It goes onto a **Mainline card — any of them**, not only a
grade — and takes no square in anybody's Office Area.

What it does: trains on that card **will not rear-end each other**. A following train is held short
of the one ahead instead of running into it, so the Superintendent has no §8.1 judgment to make and
no collision is scored. It is the only thing besides a Red Flag that prevents a rear-end collision
out on the Mainline, and unlike a Red Flag it stays on the card for the rest of the game.

On the board a card carrying it draws a **signal mast with a lit lamp** at its top-right corner; the
three grade helpers draw as **BRK**, **AIR** and **HLP** beside the card's name. Realignment draws
nothing, because a realigned card simply becomes the card it was converted into.

## Heavy Grade orientation is settled, not missing

Heavy Grade orientation is **rolled from the seed**, not chosen by a player. **This is a decision,
not a gap.**

The card prints "(Up)" and "Player sets orientation", which assumes the card has an owner. This one
does not: the Division is laid `DP · Mainline · Office · Mainline · … · DP`, so a Heavy Grade always
sits **between two districts**, or beyond an end Division Point beside one — never inside a single
player's district.

Orientation is not cosmetic. Brakeman and Airbrakes help a train running **downhill**, Helpers helps
one running **uphill**, and odd-numbered trains run west while even run east. Turning the card
around decides which modifiers are worth anything and which direction of traffic is favoured, for
the whole game. Handing that to one of two neighbours advantages them over the other, and neither
has a fair claim to it.

**Re-opened and closed again on 2026-08-23**, when giving the choice to the Superintendent was
considered and rejected. Jesse's call: v0.5.0's ruling stands. Rolling from the seed is
deterministic, roughly even (51/49 east/west over 400 games), identical in solitaire and
multiplayer, and keeps setup non-interactive — the game has no setup phase, so the question would
have to interrupt play before the first Local Operations, in the minority of games that deal the
card at all (20% at one player, rising to 50% at four).