NZR RM class (Edison battery-electric)
The NZR RM class Edison battery-electric railcar was a popular and successful railcar that ran in Canterbury, New Zealand for eight years. The prototype, RM 6, was arguably the first successful railcar in New Zealand, but the type was not developed into a class.
The railcar had a wheel arrangement of Bo-Bo under the UIC classification system, weighed 32 tonnes (31 long tons; 35 short tons), had driving controls at each end, and with an engine output of 90 kW (120 hp), it travelled comfortably at 60 km/h (37 mph). In appearance, it looked like a cross between a regular railway passenger carriage and a tram; side-on, it looked like a passenger carriage, but each end resembled the front of a tram from that era. The body was built by Boon & Stevens, the noted tram-car builders of Christchurch, in 1926, and equipped with Edison battery-electric equipment.
Capable of carrying about 70 passengers, with 60 seated, and a separate smoking compartment, the railcar had a range of about 100 miles (160 km) on one battery (charge). Apparently a layover of about 4 hours was needed to recharge the battery. When introduced the railcar was billed as capable of being used on the Christchurch-Little River and Christchurch-Rangiora runs as well as being available for charters to other North Canterbury destinations. Being electrically powered and running on a storage battery, the railcar was very quiet, with the only wheel noise being noticeable when in motion.
The New Zealand Railways department claimed it could cover the 36 miles (58 km), 12 stops, journey between Christchurch and Little River in 1 hour and 7 minutes at an average throughout speed of 30 miles per hour (48 km/h). They also claimed that passengers could board in 8 seconds or less stating "the stop at one of the smaller outlying stations to pick up a passenger was so brief as to be barely perceptible."
The railcar was initially built in 1926 to operate services through the lengthy Lyttelton rail tunnel on the Lyttelton Line, but around this time, the Lyttelton Tunnel was electrified and the railcar was instead assigned to the Little River Branch, commencing services in early 1927. Previously, the Little River Branch's passenger services had been provided by mixed trains that carried both passengers and goods and ran to slow schedules as they had to load and unload freight regularly, and the Edison battery-electric railcar was introduced as a faster and more desirable alternative. It ran between Little River and Christchurch twice each way each day, completing the journey in 69 minutes.
The railcar was popular with passengers and crews; it was fast for its time for a rural train on New Zealand's national rail network, and ran cleanly and efficiently. However, it lasted a mere eight years, as it was destroyed in a depot fire in Christchurch in 1934. Conditions created by the Great Depression meant it simply was not possible to build a replacement, and the Edison battery-electric railcar's legacy was left as that of a promising and unique experiment that may have achieved its full potential in more prosperous times.
The bogies of the car were dumped on the Oamaru foreshore with other old locomotive remains to prevent erosion of the Oamaru railway yards. In 2009 the bogies of RM 6 and the locomotive remnants were removed from the foreshore. The locomotive remnants were placed in the care of the Oamaru Steam & Rail Society while the bogies were donated to the National Railway Museum of New Zealand, and placed in storage at Ferrymead Historic Park, awaiting refurbishment.
- Page 10, Volume 2, Issue 10, The New Zealand Railways Magazine. (February 1, 1928)
- Leitch & Scott, p 65
- Leitch & Scott. p 65
- Churchman, Geoffrey B., and Hurst, Tony; The Railways Of New Zealand: A Journey Through History, HarperCollins Publishers (New Zealand), 1991 reprint
- Leitch, David, and Scott, Brian; Exploring New Zealand's Ghost Railways, Grantham House, Wellington, 1995. ISBN 1-86934-048-5 (Revised edition 1998.)
- Edison Storage Battery Rail Car. Successful In Canterbury District The New Zealand Railways Magazine, Volume 2, Issue 10 (February 1, 1928), New Zealand Government Railways Department, Wellington. Archived by New Zealand Electronic Text Centre, Victoria University of Wellington Library.