2-8-8-8-4 2-8-8-8-4 Under the Whyte notation for the classification of steam locomotives, a 2-8-8-8-4 has two leading wheels, three sets of eight driving wheels, and four trailing wheels. Other equivalent classifications are: UIC classification: 1DDD2 (also known as German classification and Italian classification) French classification: 140+040+042 Turkish classification: 45+44+46 Swiss classification: 4/5+4/4+4/6 The equivalent UIC classification is to be refined to (1'D)D(D2') for these engines. Only one 2-8-8-8-4 was ever built, a Mallet-type for the Virginian Railway in 1916. Built by Baldwin Locomotive Works, it became the only example of their class XA, so named due to the experimental nature of
1/2 + 1/4 + 1/8 + 1/16 + ⋯ 1/2 + 1/4 + 1/8 + 1/16 + ⋯ In mathematics, the infinite series is an elementary example of a geometric series that converges absolutely. There are many different expressions that can be shown to be equivalent to the problem, such as the form: 2 + 2 + 2 + ... The sum of this series can be denoted in summation notation as: As with any infinite series, the infinite sum is defined to mean the limit of the sum of the first terms as approaches infinity. Multiplying by 2 reveals a useful relationship: Subtracting from both sides, As approaches