Tip #1.When
your mainline has a bottleneck at some bridge(s), you can decide to
replace them with shorter, faster bridges or just add more bridges. The
better and more expensive solution is to build an island, and then to
build fast cantilever bridges between them. But: making island is
expensive! 50K for the first upward land terraform, and 30K for the
second! Then, when you are done buoilding the islands, you need for
brdiges 30K minimum each.... Ouch! that must hurt. Not so with this
tip! This tip might save you up to 50% on those bridges!
To successfully perform this trick you need some practice. But first: how do you get it cheap? Lets see, step by step.
Step 1: locate your slow bridge(s), and make sure to have at least ~180K ready to spend for it.

Step 2: remove the bridge(s).
Step
3: determine the location of the island. This might be a precise
things, as sometimes you have exactly the amount of space you needed,
so you cannot make errors. The way this goes: open builder, try ty make
a new station (1x7). You can count 9 tiles easily that way. Now count 9
water tiles (max bridge size is 11, heads included). Add one corner,
and we have the maximum location of the first side of the island. Place
a buoy if you do not want to make errors, and double check again. If
you determined the spot where the island has to come, we are halfway.


Step
4: the hard part. Now what you need to do is press 'w' (terraform land
up). Then you twice terraform two corners where the island needs to
come. Then, as quickly as you can, press 'u', and buyup the four
corners of the island. If you do this fast enough, it will only cost
you about 2K for the four corners. The slower you do, the more
expensive it becomes. In some cases, it is impossible to be fast
enough. usually, you can get 3 cheap corners.


Step
5: build the bridges. Now they are, for each corner you fixed, 10K to
20K cheaper. On foru bridges, this can save you up to 80K! Nice, huh?
notice how the left bridge is cheaper on the first screenshot!


If
you are not succesfull in buying the land quickly enough in step four,
the sign will be expensive. The difference in an expensive bridge or
expensive sign is zero. So you can always try this, if it doesnt work,
it will not cost you extra.