There is a SP1 for TRS2009 WBE, but wether you *should* install it, is another story. Some people claim it causes more issues than it solves, whilst others claim it fixes problems. Your mileage may vary, but I run it here, with no problems.
And in addition , by entering the start menu of Trainz , in the lower right corner it will show your build number , there are updates to builld 38599 available :
