1825 for 1846 players

This isn't a complete guide to the rules, just a guide to the most
important differences.

Privates don't have special powers, and aren't drafted or auctioned.
They're just dealt out at the start to provide an order of play. They
do provide a modest income. They don't expire, but will normally be
sold later to raise cash or get an extra railway certificate in under
the certificate limit.

Major Companies have an initial stock price fixed by the rules. They
are made available in a specified order. They have "full
capitalisation"; once 60% of the company is sold, it floats, gets 10x
its stock price as initial cash, but there are no Treasury shares; the
only way for the company to get more money is to withhold. The
remaining four shares in the "IPO" remain for sale at the original
price, even if the market price of the company changes.

Early on in the game there's only one, and then only a few, companies
to invest in. It's not remotely like '46 where normally everyone
starts their own company; at the start everyone buys into the LNWR,
and the question is when to sell up and start your own company.
Because companies can't be dumped on you, there's no penalty for
shares in the market, and you already got the money when the company
floated, the Director and the investor don't have a hostile
relationship at all.

Minor Companies are traded in 20% lumps, with the Director's
certificate being worth 40%. They come with a "baked-in" train which
can't be sold. They don't have a fixed initial price, and they receive
money as shares are sold; they start to operate as soon as they can
pay for their baked-in train. They only get one token. A Minor can
start and operate even if trains of the same type as the baked-in
train aren't normally available in the current phase.

It is permitted to sell the Director's share; there is a
"Receivership" mechanism to run a company that no-one wants 20% of
which lets it lease a train from the bank and recover. Relatedly,
there's no requirement to own a train, forced money raising, or
bankruptcy.

Shares below £50 don't count towards the certificate limit.

Like 1822, there are "towns", small stations with no token spaces that
count against a train's run. Small station hexes can grow up into
large stations with token spaces.

Brown tiles are called "russet".

As the phase changes, the number of Operating Rounds increases from 1
to 3. In the closing phases of the game, there is no train limit.

"Company credit" is a separate stock of money to that held by players,
so only players accumulating money can break the bank. The game also
ends if any stock reaches the maximum price.

Only buying shares continues a stock round. If you only sell, it still
counts as a pass.

The running order of companies is the order in which they floated. It
does not change.

Construction is normally free except in difficult terrain.

You can upgrade one tile or lay two (but they can't be in adjacent
hexes). The first tile placed on a hex always counts as a "lay", even
if the printed hex was yellow or green.

When upgrading a hex, either you must be able to reach some of the new
track on it (like 1846) or increase the value of a route one of your
trains could actually run. The difference here is that in 1846 you can
upgrade a city on the other side of the map if you can trace a route
to it; in 1825, you need a big enough train to reach it from one of
your tokens.

Station tile upgrades are weird, particularly because there are "OO"
tiles with two separate large stations, but also because of the way
that small and large stations upgrade from yellow to green (too
complex to describe here, but attention to the tile chart is
valuable). There are a handful of striped tiles that, eg, upgrade from
yellow to russet skipping green altogether. Birmingham, Glasgow, and
Manchester have their own special 'BGM' tiles. London has its own
special six-way tile.

Some hexes are reserved for specific companies; only that company can
build on that hex first.

2-Trains can be "double-headed" - run as a single 3-Train. The
autorouter doesn't understand this so you have to put the route in by
hand.  Sorry.

There are some funky trains. They don't affect the phase progression,
which runs off the regular trains, but the phase does determine when
they become available.

T-trains (tank engines) can start or end routes at small stations.
They can score two small stations on one hex. Only companies that own
them can place tile #11, the Halt. TBH, their special power isn't very
good and they're mostly bought when you can't quite afford the next
regular train.

U-trains can start and end on small stations, and their run length
only counts large stations, but they still score small stations. This
is pretty good.

2+2 trains route like a 2-train but score double.

4+4E trains plan a Route of any length and score twice the value of
any four large stations on that route.

You can't half-pay; you either pay out or withhold. Stocks can
quadruple-jump if the payout is 4x the stock price. There is no
obligation for a company to have a train, or mechanism for the
Director to contribute money to it buying one.