1820 AD (0)
Hire some extra specialists and kill 1 exposed TOW. Begin a roading project toward Ur to allow more city construction and bring the Sumerian capital into range.
IBT- Our artillery stack is bombed by every Sumerian and Babylonian bomber, and all make successful hits. We only lose 1 cavalry and 1 infantry though as one of our exposed cavalry retreats under the stack
1822 AD (1)
1 loss for a modest number of kills. Most of our artillery are out of comission for the turn from movement, so not too much available to attack.
Raising science shaves a turn off of Combustion, and we still make a modest profit. The Hague starts stock exchange and I shuffle tiles and starve the city to get Wallstreet a turn earlier.
IBT- Defeat 2 cavalry, but we lose the infantry and cavalry defending New Leidin and the Aztecs capture it. Elsewhere we exchange an infantry for a mech and TOW.
1824 AD (2)
Kill 2 cavalry and recapture New Leidin. Overall, we kill a good number of mechs and inf for 2 losses.
Found New Lawersoog on the row of hills to bring Ur into artillery range and strongly garrison the city.
IBT- We lose 2 infantry in New Lawersoog and kill an equal number of attackers. A TOW/artillery pair shells New Lawersoog during the attack.
1826 AD (3)
Science is turned down on the last turn of Combustion for a big surplus.
We lose 2 cavalry, but eliminate the TOW/artillery pair capturing the gun. We kill a good number of infantry and riflemen without further loss.
IBT- Our forces at the Sumerian border defending the captured artillery are heavilly attacked and Babylonian bombers finish them off. We lose 2 cavalry and 2 infantry. The walls of Bactra are bombed out by Sumeria.
We learn Combustion (start Mass Prod) and complete the last stock exchange.
1828 AD (4)
Wallstreet rushed in a small town well behind the front lines. City name is changed to Wall St.
We found New Tilburg and New Zwolle trapping a large number of healing Babylonian units behind our lines. With the new cultural borders we should finally be able to drive out the Babylonian stacks.
We destroy one of the Babylonian stacks and a couple of free units without loss. Also yellowline some of the destroyer/transport stacks hoping they will retreat. The hitpoint losses are low enough that we might be able to take out Ulaanbator next turn.
IBT- No attacks besides bombardment, but some injured destroyer stacks don't retreat. 3 injured mechs enter Ur, so no dice on an attack there.
Wallstreet completes, and our income takes a nice jump.
1830 AD (5)
I use almost all of our artillery to redline the defenders of Ulaanbator with a high percentage of misses. Unfortunately, as at Ur, the Mongols were using the city as a healing post and there are at least 5 infantry. Our first two elite cavalry die promoting the first defender, and there aren't enough artillery remaining to ensure the defenders will remain redlined. With the residual artillery and our cannons we are still able to take out a decent number of guerillas, a couple marines, a retreated TOW, and an infantry.
Wounded cavalry have been shifted to cities threatened by Sumerian marines.
Post-Turn
Given that Ur is a capital city with 2 wonders at a troop transit point, I would guess the city has at least 6 defenders (plus any healing units). According to the combat calculator, a 4hp cavalry has a 58.6% chance of taking out a 1hp fortified mech on grass (even if our first attackers are 5hp, they are likely to take some kind of defensive bombard hit). We can expect to take 4-10 losses capturing or destroying Ur (RNG fickleness accounted) and should have at least 18 healthy attackers to ensure taking the city. On the other hand, taking Ur will most likely permanantly destroy their annoying airforce and really hurt one of our top rivals. It appears that Babylon has around 4 bombers, so with enough infantry the red and yellow bomber range lines are not impenitrable.
In terms of research, I think we should self research up to Motorized Transport and Flight, then make the decision on self research vs. stealing. The appeal of tech stealing will partially depend on the number of techs we are behind in the Modern Age (i.e. have the AI ignored the Ecology/Modern Armor branch).