What is the bottleneck in Car Sort Level 140?

The bottleneck is the return curve because the top hook, middle stack, and lower tray bank all depend on it.

Why does the tray bank reopen in Level 140?

Because the shaft still uses the same curve when the basement closes too early.

Car Sort level guide

expert Target: 56 moves 7 colors

Car Sort Level 140 is a top-hook shaft where the middle stack must calm down before the lower tray bank can stop sharing the same return curve.

Layout: A left-facing top hook feeds stacked middle shelves, while a lower tray bank sits under the return curve.
Goal: Trim the hook first, flatten the middle stack second, and finish the basement only after the return curve belongs to the bottom half.
Opening: Reduce the top hook, free the upper stack, and keep the lower trays flexible while the curve remains mixed.
Danger Zone: If the tray bank seals before the shaft releases the curve, the whole tower freezes.
Mechanics: The return curve is more important than the colors. Once it belongs only to the lower half, the board collapses quickly.

Reduce the top hook first so the shaft stops forwarding unfinished traffic through the same return curve.
Free the upper stack before the tray bank begins to finalize.
Keep the lower trays flexible while the middle rows still borrow the same curve.
Let the tower lock from top to bottom before the base closes for good.
Finish the lower bank only after the curve no longer reverses it.

Colors in this level:

Yellow, Blue, Green, Purple, Pink, Black, Cream

What is the bottleneck in Car Sort Level 140?
The bottleneck is the return curve because the top hook, middle stack, and lower tray bank all depend on it.
Why does the tray bank reopen in Level 140?
Because the shaft still uses the same curve when the basement closes too early.