The Salamander is an amphibious vehicle used by Mr. Curtain and the Ten Men. It makes it's first appearance in The Mysterious Benedict Society and the Perilous Journey and also in the Prisoners Dilemma. On page 320 in the Perilous Journey it says: '"...That's all I- wait, do you hear that?" Reynie heard it, all right. A rumbling sound, again like thunder, only softer this time and steadier. It traveled from the direction of the meadow, growing louder and louder until the rumbling seemed to come from the ground all around them. Then the Salamander rolled into view. It was coming down the village path. Rennie and Kate crouched behind the fallen roof and peeked out. A great armored beast thirty feet long and ten feet wide, the Salamander surged forward on heavy revolving treads. Its sides were dark blue-black of gunmetal and shone dully in the moonlight...' The Salamander is the key use of transportation for Mr. Curtain and his crew, as it is 'just as fast on land as it is in water'. It's key features are its heavy revolving tank-like tracks, a metal canopy above the seating in the rear, and it's ship-like wooden steering wheel. The Salamander is very similar to a PT-2 amphibious cargo vehicle, made by the soviet union.
Diagram of the Salamander: