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Class 115 Derby 4-car DMUs

Description

While the vehicles appeared externally similar to Class 127 vehicles, there were minor differences. The Class 115s had four handrails on the cab front, the Class 127s had none. The Class 115 TCL vehicle had a slightly different window layout than the Class 127 TSL vehicle, with one full size window being replaced by two half windows where a bulkhead divided the first class area into smoking / non-smoking.

Internally they had improved seating, furnishings, lighting and wall surfaces, due to the work of the BTC Design Panel who wanted to remove the bus type atmosphere from the sets.

This is the first class.

This first view of a second class has an unpatterned moquette (the scan has added the dots).

This view of a second class non-smoking saloon shows moquette that was also used on the Class 126 Swindon units built for Ayrshire.

Only the third batch had alloy window frames.

Over the years the sets had a variety of buffers, including cut, oval and large round. In 1981 some power cars were fitted with power sanders to aid adhesion.

Modifications

Exhausts

On the rear end of the power cars the exhausts were plain pipes rising up to join into a single box - see this image. Beginning in 1965 alterations began to be made so the pipes no longer joined. By circa June 1965 at least seven vehicles had this done: 51654/62/74, 51865/81/4/95^[1]. By mid-1966 51653/4/6/8/9/60/2/7/74/5/8/9, 51862/5/6/9/70/4/5/6/81-4/6-9/95/7/9 and 51900 had been treated.^[2]

In mid-1976 two power cars (one being M51857) were fitted with a new type of exhaust silencer as an experiment. It included an expansion chamber equal in volume to the swept volume of the engine, fitted as close to the exhaust manifold as possible with large-diameter pipe leading to an increased-capacity exhaust silencer. The level of exhaust noise usually associated with these units was significant reducted in initial tests^[3].

Later on the exhausts had an additional sliencers added on the inner ends, as shown in the image.

Tail Lights

In late 1975 red bulbs were fitted to one of the two positions on each of the cab marker-lights, to operate as tail lights to that tail lamps were no longer required.^[4]

Sanding Gear

David Hatt was a commuter to and from Amersham in Autumn 1978: "One evening the 17:12 from Marylebone to Aylesbury stalled on Chorleywood bank due to leaves on the rails. I was waiting on Amersham station and watched a Class 25 pass southbound to rescue the DMU. London Transport were not best pleased by this incident, since it completely disrupted the Metropolitan Line service in the evening peak. For the next several weeks, DMUs were not permitted to run over the Metropolitan Line, and so BR operated an Aylesbury to Amersham shuttle."

"The first modification to the Class 115s was the fitting of a funnel in the guard's van, with a hose down to the bogie. This allowed the guard to pour sand into the funnel, thus facilitated sanding at the wheel/rail interface. I have a feeling that it was this modification, implemented quite quickly, which convinced London transport to lift their ban on DMUs running over the Metropolitan Line. It was either the following year, 1979, or 1980 that the sandboxes started to appear on the bogies."^[5]

The image shows this sanding gear fitted to the front bogie of M51656. The sandbox can be seen to the right of the left hand axle with a pipe to discharge the sand under the wheel.

Gangways

Vehicles began to be gangwayed in late 1986, and initially this was to create hybrid 115 DMBS/108 DTCL sets for Network South East. The first two treated were 51654 and 51878, the work being done at Tyseley.

Vehicles transferred to Tyseley would also be gangwayed. Many of the vehicles remaining in the London area would remain ungangwayed.

Other Modifications

Here are details of some of the many other modifications made to the class, detailed in LMR Traction Bulletins:

Issue 4 - October 1972

Issue 36 - May 1983

Issue 39 - August 1984

Asbestos

The vehicles were built without blue asbestos. They were included in a vehicle log kept by the RTC at Derby dated circa 1984 which included the asbestos status for each vehicle, the pages of which are included below.

In the asbestos columns the / meant they were not built with blue asbestos, in the remarks column SV meant seperate van (no access to train).