Class Cu c+/020-0231 (Locobase 5542)

Data from [], the web site of the Spanish National Railway. visited 21 April 2003. Wheelbase and axle loading from [] (18 June 2003) and RENFE's 1947 Material Movil diagram and photograph book made available by Lavagoneta. See also "Historias del vapor (VII): La familia de "las cucos" (RENFE 020-0231/240) " , Trenes y Tiempos blog entry for 23 noviembre 2014 at [], last accessed 30 December 2017; and manolo serrano, "Serie 020-0231/020-0240" on his website at [], also last accessed 30 December 2017; and Toni Nieto, "Renfe Serie 020-231 a 240 (Cu c+)", Ferropedia at [], last accessed 31 December 2017. Works numbers were 786-795.

Serrano observes that Spanish railways rarely bought locomotives whose primary purpose was terminal switching (maniobras). Instead, they depended on small, antiquated machines that could be dedicated to such service. But this decade of engines served their purpose quite well. The diminuitive class were nicknamed "cu cus", "chocolateras" (apparently their shape reminded some of an old method of boiling chocolate in a chocolate pot), or, referring to the lovingly restored example displayed at Lleida, La Chelito, thought by the Trenes y Tiempos author to memorialize a popular early 20th Century singer of variety songs.

Although petite, the design nonetheless featured such components as a Belpaire firebox, inside steam pipes that created a triangular cross-section smokebox, full cab, relatively long wheelbase, and outside constant-lead radial valve gear. Long tanks ran from just behind the stack to the cab face. Their sloping cross section, which widened toward the top, may have limited how much water could be carried safely.

All ten were taken into the RENFE in 1941. And no less than seven were later put on display or donated to museums. No doubt their small size encouraged such conservation, but the pride of place given to many of these locomotives suggests the affection many felt for such approachable workers.

0231 wound up on display at the Museo de Ferrocarril de Delicias.

0232 spent years on display on a pedestal in Valencia next to the Fuente de San Luis station. Spain's preservationist ARMF restored the 0232 and put it back in operation.

0234 is on display in Terrasa. (Nieto suggested that the locomotive labeled 0234 may actually be 0238).

0235 traveled the furthest afield and is currently housed in the Museo Elder de Las Palmas de Gran Canaria (largest island of the Canary Islands).

0236 wound up as part of the Museo de Vilanova's collection

0237 is housed inside at the Museo de la Siderurgia (Industry) de Langreo in a brilliant comination of vivid red frame and running gear, clean olive green, and black dome and smoke box.

0240 was acquired by the collection of the Alcazar of San Juan, but doesn't appeared to have weathered well.

Class 611/020-0211 (Locobase 5540)

Data from [], the web site of the Spanish National Railway. visited 21 April 2003. Wheelbase and axle loading from diagram reproduced on [] (visited 18 June 2003). See also Pere Comas, Breve Historia de la Traccion Vapor en MZA, Trensim TS10H002, Julio de 2011,p. 106. Works numbers were 104-105.