This is all amazing information! I did have my own look at the Kulja Crisis, and do think that with the Qing overthrown (something Europe is only really getting a handle on TTL in 1867, news is slow and the Europeans were notoriously bad at really caring about internal Chinese politics) with the Russian forces on the ground in the East having the best take on what opportunities exist.
Starting more rail lines East is something I see being considered, especially with some events incoming. Though how pleased the Tsar and his ministers will be about some of it is an open question because much of this will be unsanctioned.
IMHO with Qing being overthrown, China has a pretty slim chance of reestablishing control over East Turkestan aka Xinjiang. In my initial analysis I have definitely underestimated this factor.
In the course of Dungan revolt the entire regions was split into several de-facto independent states (most notably Jakub Beg’s Yettishar eventually controlling all Kashgaria and parts of Dzungaria, but also Taranchi Sulatanate of Ili that was eventually occupied by Russia, Urumqi Sulatanate, Chuguchak rebel state etc.).
Moreover, the only force in the region faithful to central government IOTL that is Manchu troops have very little reason to be willing to reintegrated into China ITTL where Qing Dynasty has been overthrown. IOTL these local Manchu officials tried to ask Russian officials (both local and in St. Petersburg via Beijing) to move the troops into Xinjiang in the name of Qing government to save these officials from rebels. ITTL both Muslim rebels and Taiping government are very grim alternatives for local Manchu so they might be willing to invite Russians in the region permanently in order to reestablish order and save their lives.
IOTL general Kolpakosvsky, Russian commander of Semirechye (bordering Xinjiang) proposed a plan in early 1865 with Russian troops entering large parts of East Turkestan (namely Chuguchak, Kulja and Kashgar region). This plan was denied by Alexander II because he didn’t want to harm their relationship with Qing (though eventually as we know Russia did partially implement it with occupying and trying to annex Kulja region).
But ITTL there is no such thing as Qing government (at least no ruling China proper) and the new government’s claim on Xinjiang is much less valid. Moreover, if I get your hints correctly Russia would meddle is Manchuria anyway which is much more important for any Chinese government than East Turkestan. Thus, Alexander II definitely shouldn’t worry about hurting relations with new government in Beijing and can give Kolpakovsky a green light.
If Russian expedition starts in 1865 or 1866 Manchu are still holding out in Kulja (which was the most important city in North-Western Xinjiang) and Chuguchak. So, while the front is wider than that of OTL 1871 campaign, unlike IOTL there is a substantial local support against Muslim rebels. While Russia doesn’t have a particularly large local force, given 1871 example (and Russian campaigns in Central Asia) I think Russia should be able to defeat local rebels and conquer another major rebel state in Dzungaria Urumqi Sultanate. After that there is only Kumul Khanate left centered around Hami which IOTL stayed loyal to Qing and fought on their side against rebels. ITTL given Qing are overthrown it might chose to switch its allegiance to Russia (or if not this not a particularly large state so it can be conquered easily).
So by late 1860s Russia might more or less completely control of Dzungaria (northern half of Xinjiang). Dealing with Jakub Beg and his Yettishar (by late 1860s fully controlling Kashgaria, southern half of Xinjiang) would definitely take a lot more time and effort though (especially considering his links to Kokand and possible British support).
Starting more rail lines East is something I see being considered, especially with some events incoming. Though how pleased the Tsar and his ministers will be about some of it is an open question because much of this will be unsanctioned.
Though this does mean the Ural Railway will get a shot in the arm earlier instead of just purely private investment.
I mean to be fair Ural Railway (as pretty much all the private railways in Russia) had a governmental guarantee on return of investment. IOTL this guarantee did eventually trigger as without the completion of Yekaterinburg-Tyumen part (it was completed as a government railway in 1882-1885) the railway was losing money (also because local factory owners had extremely beneficial condition on cargo transportation).
However, this deal was still a reasonable deal for the government: not only such an arrangement was at worst (that is if the railroad did not become profitable as happened IOTL) a private loan with decent terms used to finance a strategically important project.
It also allowed the government to reduce subsidies paid to the owners of Ural factories (IOTL in 1870s yearly subsidies averaged some 12 million rubles compared to 45 million that the Perm-Yekaterinburg railway costed with all its auxiliary branches and 15 million that Yekaterinburg-Tyumen railway costed; the entire governmental budged in 1870s was on average 500-600 million rubles)
So, if ITTL the railways to Asian part of Russia have a higher priority, Russia can encourage private investors to start building railways earlier. It is not free, Russian government is likely to eventually pay back the cost of project, but it doesn’t require governmental spending at the moment.
So, if there is a political will (and it looks like ITTL it may be top priority for Russia) the government can provide a guarantee in the same way it did IOTL but a few years earlier.
Moreover, there was a private investment consortium willing to finance Nizhny Novgorod-Kazan-Yekaterinburg-Tyumen railway given similar guarantee. IOTL the government was reluctant to provide such a guarantee (although IOTL in 1875 it decided to build the railway with governmental money; this project was stopped though because of Russian-Turkish War approaching, as I mentioned in my previous post), but if ITTL Asia has a top priority in late 1860s-1870s, it Alexander’s ministers might be willing do so ITTL.
If this does indeed happen there is really nothing that prevents both Ural Railway and the first section of Siberian railway (Nizhny Novgorod-Kazan-Yekaterinburg-Tyumen) from being built by around 1875. And with the proper link to main Russian railway network both railways are likely to be profitable from the beginning.
The long term population trends in Manchuria will be interesting. Doing some of my research for the 1890s beyond North America recently, and I've been learning there were efforts to get more Russians settled out east because of land problems in Russia proper. It was Witte (IIRC) who saw settlement out there as a sort of pressure valve to get the many unhappy peasants and who flooded the cities to work - and in doing so partially ended up radicalized - so the priorities of Russia could be met by this kind of ambitious project, especially as they will be paying attentions to efforts in America.
The population of Manchuria in the second half of XIX century is a quite contentious topic.
We have the official data of registered settlers for several years, but the academic consensus is that these numbers are highly undercounted. Indeed, the local Han settlers had incentive to avoid being counted even after 1887 when Qing government lifted the last limitation for Chinese settlement in Manchuria (partial removal of limitations was done in 1860, but this was only for certain areas in the Northern Manchuria) since being registered meant being taxed and settler wanted to avoid it.
All the numbers below a given for contemporary province borders (different from modern borders).
The official data for 1862 (from Kang Chao’s
Demographic Development of Manchuria):
Manchuria total: 3332 thousand people, Liaoning: 2818 thousand people, Jilin: 329 thousand, Heilongjiang: 185 thousand (there is no data for Heilongjiang in 1862, but it is assumed that the population there grew at the same rate as for Jilin).
But once again these numbers are definitely undervalued, the question is by how much (there are different opinions ranging from something close to official data to Manchuria having over 20 million people in 1890s).
The numbers I personally think are somewhat reasonable (mainly because they correspond well to the numbers in other sources) are inferred form Isett’s total population of Manchuria from
his State, Peasant, and Merchant in Qing Manchuria. Here are the numbers for 1862:
Manchuria total: 6770 thousand people, Liaoning: 5724 thousand people, Jilin: 668 thousand, Heilongjiang: 375 thousand
Of those at most 2.5 million are not Han.
IOTL there was 2.5 million of non-Han population in 1910, including 1692 thousand Manchu and 658 thousand Mongols.
Presumably ITTL several hundred thousand Manchu escape from mainland China, but we are some 50 years earlier and should account for natural growth that happened IOTL.
Even if the real numbers are somewhat smaller than the ones above, only the official population of Manchuria is larger than the population of the whole Siberia in 1862 (not counting Steppes District aka Kazakhstan, but there the majority of population is nomadic).
If we take more believable Isett’s number then Manchuria is 1.5 more populous than whole territory of Russia over the Ural Mountains (in 1862 Siberia had 3141 thousand people, Steppes District 1485 and Manchuria 6770).
So overall there is no way in hell Russia would be able to assimilate the whole Manchuria. This doesn’t prevent Russia from being able to conquer and fully control it though (the same way it did with Central Asia or Caucasus).
Moreover, Russia can probably implement divide and conquer policy giving non-Han population substantial privileges and these population groups are large enough for this policy of having a chance to succeed (the same way Russia gave privileges to Caucasus Christians despite those were a minority).
Another factor to consider that the 85% of population (both in total and even more so Han) is concentrated in Liaoning.
Now it is extremely important part of Manchuria, it has an access to Yellow Sea, it has insanely abundant natural resources (most notably coal around Fushun and iron around Anshan allowing Japan to build an industrial giant Showa Steel Works), so it’s not Russia would willingly part with it.
However the government may choose to treat this region differently from the two northern provinces (where there is at most 1 million people and most of those are probably non-Han).
So, Russia may attempt to settle and assimilate two former northern provinces (the same way it did with Northern Caucasus and Northern Kazakhstan) while considering Liaoning as populated by “foreign people” (инородцы in Russian, basically non-Slavs) which of course won’t prevent some Russian settlement there (once again in the same way Tashkent and Chu Valley around Bishkek were settled by Russian-speaking population).
This is an extremely ambitious project of course and only the TL author may answer if Russia would succeed (if it attempts to do it that is).
Money no, ambition, yes.
The mess that us Russian finances is a multifaceted hydra that I'm not sure I can find a way to unpack, but a different aspect of military spending does present itself. So I do think they will be building north rather than south to simplify things. There's going to be a response to future Chinese railway investment (which will take a different shape) so money going both ways is going to be seen as a must in Russia.
As mentioned in my post above Russia does not necessarily has to spend governmental money for it at least not immediately. What is has to do is to guarantee the private investors return on their investment (and there were private investors willing to finance both Ural Railway and the first section of Siberian railway in late 1860s provided they had such a guarantee).
Of course, it is still a serious obligation on the government part, but it doesn’t require it to write the check
straight away (and as we know it now definitely worth it in the long run).
IOTL the government worried that the railway would never be profitable (which sounds ridiculous for us now), but even if they have the same doubts ITTL they might be more willing to risk it since Russian ambitions in Asia are much stronger (as even if there are doubts about economic value of the railroad, its strategic and military importance is unquestionable)
The status of much of Central Asia is really up in the air right now. In theory, China controls what us modern Xinjiang, but in reality the region is deep in the Dungan Revolt currently. Tibet is a tributary of China, but is at best paying lip service to the new court in Nanjing and everyone knows it. That means that opportunistic agents in Russia could conceivably slice territory away, but it depends on the new dynasty being that willing to be accommodating in the 1870s. I do have a rough idea of where those borders will end up.
Well China doesn’t control Xinjiang, it owns it (and some countries such as Ottoman Empire recognized the new states by 1870s). The only part of the region loyal to the government was Kumul Khanate around Hami and I have serious doubts that it would retain loyalty to non-Qing government. Moreover in 1865 there are a few pockets of Manchu resistance in Xinjiang (Kuldja, Chuguchak) and ITTL they really have no one to look for protection other than Russia.
Will Russia act according to Kolpakovsky plan in such a conditions ITTL is another question. I think it would, but there may be factors I don’t see.