SS Ext. Chasis appears in my production box but I can`t build it...

[Muadib]

Hi there,
I wanna win the game by space race conditions.I need to build the SS Ext. chasis, I`ve researched the required technology.The required resources, which are Al. and Rubber appears in my city resources, even the SS Ext. chasis appears in my production box, but I `ve to mention that it`s "pale", like the production the city is currently working on.And it doesn`t let me build it.I also have to mention that the resources (Al. and Rubber) are in a city which is not connected by Road but by Harbor and Airport and since those resources appear in other cities resouce box, why doen`t let me build it.......
I`m really exhausted.
HELP.

[damedam]

According to your description, I am pretty sure that one of your other cities is already building it. Noted that auto city governor may build anything unexpected. So check the production list of your empire.

[Muadib]

Hi,
I forgot to mention that, no other city is building it.It`s the same for all the cities.
Any other reason...

[Qilue]

Have you,

a) disbanded a unit
b) rushed some other improvement by normal means

Since SS parts are treated like wonders, doing either of these things will prevent the switch.

[Muadib]

@Qilue
Could you be a bit more specific?
What does those two have to do with my problem?....
Thanx.