UPDATE 2-Koppers Holdings posts surprise Q1 profit, shares up

* Posts surprise Q1 profit

* Sales fall 18 pct to $272.7 mln

* Says not prepared to give specific 2009 outlook

* Sees positive seasonal impact in Q2

* Shares up as much as 21 pct (Recasts; adds analyst comment, details, conference call comments, updates share movement)

May 7 (Reuters) - Carbon-compounds maker Koppers Holdings Inc (KOP.N: Quote, Profile, Research) posted a surprise quarterly profit, helped by higher sales of its railroad and utility products and lower costs, sending its shares up more than 21 percent.

Sales for railroad and utility products rose 17 percent to $127.2 million, helped by higher volumes for crossties, which are used as a base for railroad tracks, sold to big freight railroad companies.

The railroad and utility unit's operating margin rose 3.1 percentage points to 9.7 percent, while the segment generated an operating profit of $12.3 million -- a 70 percent rise.

The company expects the second quarter to have a positive seasonal impact on demand for its products, which normally declines during periods of inclement weather.