Older toy engines were often lead soldered. Damaged boilers are potentially dangerous. Age, and accidents take their toll on these lightly made engines. Watch for indications of weak boiler seams, solder repairs and dents. Many American and European engines are no longer made. Damaged or missing components are nearly impossible to replace. Can you say "Display Only Engines"? Watch for photos that mask damage a seller is attempting to hide. When in doubt, ask for photos of specific angles and features. Missing view angles are dead give aways. Avoid steam engines with foreign bolts or screws, sealed ports or damaged or disabled relief valves. This kind of damage is usually unrepairable. Today, very nice engines are being offered by sellers intent on stealing your money. Zero feedback, a low buy it now price for a super nice engine with a Baltic or Asian location are huge red flags. When in doubt, ask for specific items to be placed in additional photos. Have fun, but remember... Cautious enthusiasm is a very good idea until experience is on your side.