the permission of the author, Bill Becket, here are some notes about
a couple of what can be contentious subjects: double heading and
Bill Becket produces a fine series of books entitled "The District Controller's View" through his company Xpress Publishing The website is well worth a look.
There seems to be quite a degree of confusion regarding double-heading (ie two engines at the head of the same train) and a few words of explanation might clarify the position.
There were two reasons why a train might be worked by two engines:
1. Because the train was over the weight limit for one engine.
2. Because attaching a second engine to a train was an alterative to running it light from one station to another.
THE LEADING ENGINE: It is often stated that the pilot engine in some parts of the country had to be placed inside the train engine - a statement that is almost entirely erroneous since there was (apart from the exception given below) no hard and fast rule on the matter. Usually because the assisting engine was only travelling for part of the journey, it was more convenient to couple it as the leading engine and in fact in almost every case of piloting, the assisting engine was the leading engine.
GWR/WR: The exception to the rule existed on the GWR where engines were grouped into three classes. Class 1 (superior) were 4-6-2 and 4-6-0 engines, class 2 (inferior) covered everything else except for 0-6-0 tank engines which were inferior to class 2.
With steam-hauled GW trains that were double headed on level or falling gradients, the superior engine had to be leading. This meant that a 4-4-0 had to be coupled inside a 4-6-0 although since 4-6-0 engines were all but universal in WR passenger workings, it was rare for a pilot to be coupled inside. (There was a considerable amount of small-print on the subject and on the more notorious inclines of the GW, 43xx 2-6-0 and all but the smaller 2-6-2T's were regarded as 'superior' engines.
When using an engine to assist a gw steam-hauled passenger train to climb an incline, the assisting engine had to be coupled to the front of the train.
These strictures did not apply to diesel engines which when assisting any type of engine, could be placed inside or outside the train engine.
SCOPE OF DOUBLE HEADING: Generally speaking, trains could be double-headed without any especial formalities being observed. There were a few restrictions although when taking charge of a section of railway, it was essential to know what they were. On the GN, for example, you could not double-head Pacific/V2 engines whilst on the Southern almost every large engine (with the exception of the WC Pacifics) was barred from double-heading.
ASSISTING IN REAR (BANKING). This was totally different from double-heading and was prohibited except for specially nominated sections of line where it was strictly regulated. see below.
ASSISTING IN EMERGENCIES. The substance of what has been written above did not apply to failed trains and other emergencies where an assisting engine was required..
Banking - assisting a train in the rear - tends to be seen as analogous with double-heading whilst in fact the two were unrelated. As discussed yesterday, double-heading was a routine matter which could be resorted to without any particular formalities. Banking, on the other hand, was strictly prohibited except where expressly permitted. To give an idea of its scarcity, on the main line between Crewe and Euston, there were only two locations where banking was permitted. One was from Euston itself where trains could be assisted in rear as far as Camden and the other was on the Northampton line where up goods or ECS trains could be banked from Northampton Castle to Roade.
Where banking was permitted, the authorisation was accompanied by a number of conditions as to the types of trains that could be banked, whether the banking engine had to be coupled and piped to the train, etc. In almost every case a train to be banked had to come to a stand before the banking engine was admitted to the rear but the exceptions - ie where the banker could follow the train and 'catch up' with it - were enumerated in the conditions.
Double-headed trains were signalled normally but banked trains were signalled by an addition 2-2 signal (one for each banking engine) after the train entering section had been sent.
General note:- Piloting and Banking.
I should stress that they did not necessarily apply during emergencies such as engine failures and the like. If, for example, a train failed on a section of the main line where banking was prohibited but the obvious course was to propel it by an engine or another train to a point where a replacement engine could be put on the front, then this is what you might do. These, however. were exceptional circumstances which would be dictated by the Controller.