I'll dedicate this post to define Ralph's capabilities and limitations according to the stories, specifying the sources. You might want to check it every now and then, because I'll be updating it as I re-enjoy all the Elongated Man's stories.
- Ralph is capable of lifting 2 men with each arm (Detective Comics #358). In Detective Comics #361 he also juggled a big man.
- In Detective Comics #361 he holds seats with children in different parts of his body first as a human ferris wheel, and then as a human roller-coaster.
- She can lift a person and carry him vertically (Flash #115) or horizontally while stretching without collapsing.
- He can stretch at "rocket speed" (Flash #119).
- In Detective Comics #344, a caption box establishes that 100 yards is Ralph's stretching limit.
- Detective Comics #331 showed that he can squeeze to pass through a keyhole and issue #337 that he can pass through the valve of a tire as well.
- In Flash #252 Ralph demonstrated the never before seen capability of molding his face to look like other people. This power has rarely been displayed again; however, in Europe '92, he molded his hand to look like the head of a bulldog.
- Ralph can resist Flash using him as a treadmill to run at light speed (Justice League of America #150).
- Ralph is highly resistant to sonic attacks. In Justice League of America #258 he takes Vibe's "best" without trouble and in Europe '92 he grounds a sonic weapon attack.
- While some stories have him getting knocked out (Detective Comics #572) or breaking an arm from stretching it too long (Justice League of America #211), both of which at least to me, sounds unreasonable, Justice League of America, vol. 2, #6, has Amazo using Ralph's powers to resist Hawkgirl slamming her mace halfway through his head. Which makes, since since Ralph has been able to stretch during all of his hero career without getting wrinkles or striae.
- Detective Comics #337 showed that he can get inside a tire and survive a car ride there. Which implies that he can survive high temperatures.
- In Batman #177, he grew twice his size evenly to look like a giant Batman.
- In Detective Comics #337 he shrank to fit inside a tire.