Leonhard has seen and approved this document, so at the time of writing these rules should be regarded as the official way to play. Bear in mind that Leonhard changes his mind quite frequently.
Comments are welcome. This is version 1.2
My thanks go to Bill Baldwin, David Hecht, Chris Lawson, Dane Maslen, and Leonhard Orgler for their assistance in compiling this document.
There have been at least two published versions of the map. One, released in late 1998, contains three errors. The hex north-west of Trieste should contain the Wocheinerbahn Mountain Railway. The hex south-east of Salzburg should have a mountain symbol. In the preprinted Budapest hex there should be track running from the northern city (Buda?) to both the north-east and the west. [Straightforward printing errors.]
{I.7} The price of the Arlbergbahn together with the Nordtiroler Staatsbahn may not drop below zero; if all players pass when it is offered at Kr5, the first player must take it for nothing. [The rules allow the price of the Albergbahn to reach arbitrarily low values.]
{II.1, V.14, XII.6} Mountain railways (the "Private Companies") close on the purchase of the first "5" train, and no earlier. In particular they do not close when track gets laid on their home hexes. [An early translation, published (in good faith) by Nick Wedd, suggested that the private companies do close when their associated passes are built. There is no support for this in the German rules.]
{II.2, VII.1, VIII.2, VIII.4} Coal companies may not own passenger trains. They may run one goods train each operating round, running from the associated coal mine to or through no more than the train's number of large cities. A train run by a coal company can run on a route consisting of the mine and only one town or city. [Most of this is in the rules, though often overlooked. {VIII.2} implies that a section of track with just a coal mine and one town or city is not a legal route; this is an error.]
{IV.2.6, XI.11} The operating order for major corporations is determined dynamically. That is, the highest-priced corporation operates first, then the corporation with the then next-highest price next, and so on. Thus, stock sales in an operating round due to forced train purchases may cause a change in operating order for corporations operating later in the round. [Most 18xx game rules don't say whether the operating order is determined statically or dynamically, and 1837 is no exception.]
{VI.1} When upgrading tiles, it is permissible to upgrade any reachable city even if none of the new track on the tile is reachable because of the tokens of other companies of corporations or because there is no new track, provided that the other requirements are met. [Without this clause it's hard to upgrade Wien and impossible to upgrade Budapest or "T" cities to brown.]
{VII.1, VIII.2, VIII.4} All minor companies and major corporations may own either goods or passenger trains, or both. When their goods trains run, their routes may extend from any coal mine, to or through no more than the train's number of large cities, at least one of which must have a token of that company or corporation in it. A route which includes a mine and only one city can be used to run a goods train. [As above, {VIII.2} is incorrect. An early translation, due to Stuart Dagger, stated that goods trains could only run to coal mines owned by the company or corporation, and it was widely assumed that major corporations could only own the coal mines associated with their exchange shares.]
{VII.4} When determining distances for calculating the cost of tokens, the path chosen may not go off the hex grid, though it may cross hexes containing coal mines. [Distances are calculated "as the crow flies" but the crow doesn't have a passport, as in 1835.]
{VII.7} When laying tokens, the route between a corporation's home station and the new one may involve back-tracking. [This rule is often overlooked, probably because 1837 is the only 18xx game with this rule. It helps the Bosnisch-Herzegowinische Landesbahn enormously.]
{VII.9} The k.k. Staatsbahn must keep its tokens in Vienna until the Vienna tile is upgraded to brown. Similarly, the Ungarische Staatsbahn must keep its tokens in Buda and Pest until Budapest is upgraded to brown. [{VII.9} also says that no company may have more than one token in a hex, and the excess are removed without compensation. This rule is one that should not have been copied from 1835.]
{VIII.4, XI.4} The number of trains in the set is a fixed limit. If none are available, corporations are relieved of their obligation to own a train. [Either there must be an infinite number of the largest train available, or a rule must exist to cover what happens when they run out. Choosing the latter brings 1837 into line with 1835.]
{IX.6, IX.7, IX.8} When a major corporation pays half dividends, or when the Eisenbahn Pest-Waitzen or Eisenbahn Pest-Czegled run, payouts will be calculated exactly and then all fractions are rounded in favour of the Bank. For example, if a major corporation earns Kr50 and elects to pay half dividends, the company will receive Kr25 and a shareholder with 30% will receive Kr7. [The rules don't say how to handle fractions. This way is as good as any, though it's not the same as either 1870 or 2038.]
{XII.2} When the first 3+1-Train is bought, the train limit for all coal and minor companies except the minor companies of the Ungarische Staatsbahn drops to 1. The train limit for the minor companies of the Ungarische Staatsbahn stays at 2 until they close. [This is what the train summary card says. The rules don't make an exception for the Ungarische minors. The designer now says that the rules are wrong and the summary card is right, though he has in the past ruled the other way. The game is, in my opinion, equally playable with either ruling.]
{XII.3, XII.4, XII.5, XII.6} If the Suedbahn, k.k. Staatsbahn, or Ungarische Staatsbahn form during an operating round, i.e. because the critical train was purchased, they will not run during that round. If formed at the start of a subsequent operating round, they will run that round. [The rules don't say whether these corporations can run in the round in which they are formed, or not, though {XII.3} does include clauses to handle the Suedbahn running in the same round as its constituent minors.]
{XII.4, XII.6} The directors of the Mohacs-Fuenfkirchner Bahn (Ungarische Staatsbahn minor #2) and the Eisenbahn Pest-Czegled (Ungarische Staatsbahn minor #3) must convert the companies into shares of the Ungarische Staatsbahn on the purchase of the first "5" Train if they have not done so earlier. The holders of the non-director's shares of the Eisenbahn Pest-Waitzen (Ungarische minor #1) and the Eisenbahn Pest-Czegled must convert their shares when the respective directors convert theirs. These conversions are done simultaneously, and the director's share of the Ungarische Staatsbahn may only shift after all are done. [The rules don't impose a time limit for converting these shares.]
{XII.5} The directors of the Kaiserin Elizabeth-Bahn (k.k. Staatsbahn minor #2) and the Kaiser Franz Joseph-Bahn (k.k. Staatsbahn minor #3) must convert the companies into shares of the k.k. Staatsbahn on the purchase of the first "4+1" Train if they have not done so earlier. These conversions are done simultaneously, and the director's share of the k.k. Staatsbahn may only shift after both are done. [The rules don't impose a time limit for converting these shares.]
{XII.3, XII.5} If the k.k. Staatsbahn is not yet formed but may do so at the start of a round, the decision about whether to do so is made by the owner of the Kaiser Ferdinand-Nordbahn after any exchange of Coal Companies. Once the k.k. Staatsbahn has formed, the owners of the Kaiserin Elisabeth-Bahn and Kaiser Franz Joseph-Bahn make their decisions whether to fold into the k.k. Staatsbahn starting with the k.k. Staatsbahn director and proceeding clockwise. However, the directorship of the k.k. Staatsbahn may only shift once all decisions have been made. [The rules are silent about this.]
{XII.3} When the Suedbahn is formed, and several players tie for having most shares, the one who owned the lowest-numbered minor becomes the director. If no tying player previously owned a Suedbahn minor, the one more nearly to the left of the former owner of the Wien-Gloggnitzer Eisenbahn becomes the director. [The first clause is in the rules but often overlooked. The second covers a situation which is unlikely to occur in practice.]
{XII.3} When the k.k. Staatsbahn is first formed, and several players tie for having most shares, the one who owned the lowest-numbered minor becomes the director. If no tying player previously owned a k.k. Staatsbahn minor, the one closest to the left of the former owner of the Kaiser Ferdinand-Nordbahn becomes the director. Once a director has been established it can only shift if the new director owns more shares than the old. [The first and third clauses are in the rules but often overlooked. The second covers a situation which is unlikely to occur in practice.]
{XII.3} When a corporation operates, it may not run any trains inherited from predecessor companies which have already operated that round. [This clause is in the rules, but in a section describing the formation of the one corporation where it can't happen.]
{XII.3} If a major corporation pays a dividend, money payable in respect of an exchange share from a company which has already operated this round is paid to the Bank. [Again, this rule appears in a section covering a part of the game where it can't happen.]
{XII.4, XII.6} If the Ungarische Staatsbahn is not yet formed but may do so at the start of a round, the decision about whether to do so is made by the director of the Eisenbahn Pest-Waitzen after any exchange of k.k. Staatsbahn shares. Once the Ungarische Staatsbahn has formed, the owners of the other Ungarische minors make their decisions whether to fold into the Ungarische Staatsbahn starting with the Ungarische Staatsbahn director and proceeding clockwise, except that should the director of the Eisenbahn Pest-Czegled decide to fold, the owner of the other half must immediately fold his share in, too. However, the directorship of the Ungarische Staatsbahn may only shift once all decisions have been made. [The rules are silent about this.]
{XII.4} When the Ungarische Staatsbahn is formed, and several players tie for having most shares, the one who directed the lowest-numbered minor becomes the director. If no tying player previously directed an Ugnarische Staatsbahn minor, the one who owned the lowest-numbered Ungarische Staatsbahn minor becomes the director. If this does not resolve matters, the one closest to the left of the former owner of the Eisenbahn Pest-Czegled becomes the director. Once a director has been established it can only shift if the new director owns more shares than the old. [The first and third clauses are in the rules but often overlooked. The second covers a situation which is unlikely to occur in practice.]
{XII.6, XIV.4, XV.2.1} At the end of the game an exchange share in a major corporation of which the director's certificate has not been sold is worth nothing, although it still counts against its owner's certificate limit. If the director's certificate has been sold the exchange share is worth the current stock price even if the corporation is not floated. [None of this is clear in the rules.]
{XIII.2} A stock round ends when all players pass consecutively. The Erstkaufsrechtskarte is given to the player to the left of the one who last made a transaction. [The rules say that sales do not cause the priority to pass round, but that turns out to be an error. 1837 should be like most other 18xx games in this respect.]
{XIII.4, XIV.5.3} Share prices rise for "all sold" when there are no shares in the initial offering or bank pool at the end of a stock round; there may be some exchange shares as yet unconverted. The share price will move up and right if the director owns 40% or less, even if he or she owns Coal Companies which will bring his or her holdings to 50% or 60% at the start of the operating round. [The rules aren't clear whether unconverted exchange shares prevent a coroporation's price rising.]
{XIV.5.1} If there are several Major Corporations with associated Coal Companies not folded in, they are dealt with in the order in which they would operate. For each such Major Corporation, exchanges are made starting with the Director and proceeding clockwise. [The rules don't say what order these decisions are made in.]
{XIV.5.2} When a coal company folds into its associated major corporation, that corporation may only discard enough of the coal company's trains into the Bank Pool to bring it to the current train limit. It may not discard trains it previously owned, even if the coal company's trains are better. [The wording could be taken to imply that if the major corporation would be over the train limit if it took all the coal company's trains then it could discard all of them, even the ones it had already. It has been widely assumed that a corporation could discard trains it already had in order to comply with the train limit.]
{XV.1} If the Bank runs out of money during a Stock Round, the game will end after the next operating round. [The rules don't cover this case.]
{XV.1} The game ends after the next end of an operating round after the bank is exhausted, and not after a complete set of operating rounds. [Some players miss this clause and assume that 1837 resembles 1830, 1870, etc. in this respect.]