I may be in error about the Ohio and Mississippi line being the only one 
available.  The Terre Haute, Alton and St. Louis line may have been 
available.  I have not found much solid information about it except that 
it was described as"poorly engineered, indirect, and financially tenuous".

On 4/10/22 11:09, Scott Holmes wrote:
> The problem here is that the St. Louis, Vandalia and Terre Haute 
> Railroad was not complete until 1870.  The only line east of St. 
> Louis, that I know of, was the Ohio and Mississippi, completed in 
> 1857.  It will take some untangling of railroad history to determine 
> what the actual lines were at the time of Sam's travel back to St. 
> Louis but I think there were connections between Columbus and 
> Cincinnati, probably through Dayton.  A northern route does not appear 
> to be possible.
>
> On 4/9/22 21:45, Peter Clark wrote:
>>   Thanks to Scott for his comments regarding Sam's railroad trip back to
>> Saint Louis from New York in 1854. Yes, Sam almost certainly would have
>> taken the Pennsylvania Railroad to Pittsburgh, however after a bit of
>> follow-up research, I don't believe that he took the Ohio and 
>> Mississippi
>> Railroad from Cincinnati on the last leg of the trip. instead, I believe
>> that he took the
>> *Pittsburgh, Cincinnati, Chicago and St. Louis Railroad*, commonly 
>> called
>> the *Pan Handle Route:*
>>
>> https://en.wikipedia.org/wiki/Pittsburgh,_Cincinnati,_Chicago_and_St._Louis_Railroad 
>>
>> )
>> https://www.hookedtobooks.com/funny-mark-twain-quotes/
>> The information in the Wikipedia article appears to be somewhat
>> contradictory.  However, it appears clear that Sam's path from Pittsburg
>> went through Columbus. From there, we can't really be sure based on the
>> information it supplies whether he went to Cincinnatti at all on that 
>> trip.
>> The map in the Wikipedia article indicates that the more direct route to
>> Indianapolis had been completed. However, the article equivocates about
>> when it was completed. From the standpoint of my story, it doesn't 
>> really
>> matter either way, as Sam continued through without stopping... 
>> however it
>> would be nice to know!
>>      I came across a reference previously that Sam paid $23.50 for 
>> the trip.
>>      Regarding the relative price between coach and sleeper cars, 
>> this is
>> what Wild West Magazine says:
>>      Passenger train travel during the 1880s generally cost *two or 
>> three
>> cents per mile*. Transcontinental (New York to San Francisco) ticket 
>> rates
>> as of June 1870 were $136 for first class in a Pullman sleeping car, 
>> $110
>> for second class and $65 for third, or “emigrant,” class seats on a 
>> bench.Jun
>> 25, 2018
>>
>>      Thanks again for your help!
>> Peter