1844.] 



THE CIVIL ENGINEER AND ARCHITECT'S JOURNAL 



267 



darling Abbey Church" " That its removal would involve the destruc- 

 tion of another of history's landmarks, a document of stone which 

 cannot lie, attesting the antiquity of your parish" "That instead of 

 your venerable temple founded by St. Edward, rebuilt by Edward I., 

 and again by Edward IV., you would probably get a mere brick and 

 plaster apology on a par with those modern churches which are the 

 laughing stock of Ecclesiologists." But is mere taste, or rather the 

 want of it, fit to be put in competition with the desecration of a spot 

 on which your ancestors worshipped for nearly eight centuries, or are 

 ye on these matters below that nation of savages, who, when urged 

 to emigrate, replied, " But how shall we remove the bones of our fore- 

 fathers '." 



Inhabitants of Westminster, rouse yourselves to resist the architec- 

 tural barbarians. Your ancestors rose e7i masse and successfully re- 

 sisted theProtector Somerset and his myrmidons when they attempted 

 the destruction of this church. The present most excollent Dean and 

 your highly gifted Rector are utterly opposed to the project of removal ; 

 put yourselves under their legitimate guidance — remove not St. Mar- 

 garet's, RESTORE IT TO ITS PRISTINE BEAUTi' AS LEFT TO YE BY THE 

 ILLUSTRIOUS Edward, and you will never more hear the senseless cry 

 of removing St. Margaret's to obtain a better view of the Abbey 

 Church. "Perhaps the best method to unite St. M.irgaret's with the 

 Minster would be by erecting a tomb-house or cloister for the recep- 

 tion of those mural monuments which disfigure the interior of the 

 Abbey Church, the expense of which would probably be defrayed by 

 the accession of new monuments." As an Architectural Antiquary I 

 have now done my duty ; let the guardians of the fabric do theirs. 



William Bakdwell. 

 U,ParkSlrm(, 



THE ATMOSPHERIC RAILWAY AND ROPE TRACTION RAILWAYS. 



[We are iudebteci for the fullovving paper lo Mr. Stephenson's valuable report on the 

 Atmospheric Railway (see ' Journal for June last, p. L'tJH) ; it was drawn up lay i\Ir. Bidder 

 at tile request of Mr. Stephenson.] 



A Report on tlic practical application of tlie atmospheric principle as a 

 motive power on railways, must inevitably be considered incomplete if the 

 investigation did not comprehend the peculiar circumstances involved in tlie 

 working of the Blackwall Railway, the more especially as public attention 

 has been solicited in this case. Before, however, we can enter upon such an 

 inquiry, we must carefully review the peculiarities which distinguish the con- 

 duct of the traffic on the London and Blackwall Railway. 



This railway is about 3 J miles in length, and is worked by stationary en- 

 gines of 400 and 280 estimated horse power at the London and Blackwall 

 termini respectively, the carriages being attached to a rope by grips, which 

 rope winds oif and on large drums situated at each extremity of the line. 

 The greater power at the London station is required in consequence of there 

 being a total rise in the railway in this direction of between 60 and 70 feet, 

 the steepest inclination being 1 in 100. 



There are no less than seven intermediate stations on this line ; five of 

 them, viz., Poplar, West India Docks, Limehiiuse, Stepney, and Shadwell, 

 communicate with the Fenchurch Street terminus j whilst four of them, viz., 

 Minories, Cannon Street, Shadwell, and Stepney, communicate with the 

 Blackwall terminus. This arrangement is effected by appropriating a sepa- 

 rate carriage from the termini for each intermediate station communicating 

 with the same, and which, whilst the trains are moving in either direction, 

 are detached, and by means of breaks are stopped at their respective destina. 

 tioHS. As soon, however, as the terminal train arrives at either end of the 

 line, and the rope ceases its motion, these intermediate carriages are at- 

 tached by means of grips to the rope whilst the latter are in a state of rest ; 

 so that when the rope is again in motion, these are also simultaneously set in 

 motion, and of course arrive successively at the termini in the order and at 

 intervals corresponding with the order and position of the places from which 

 they started ; and as they arrive, they are released from the rope, though in 

 motion, by the sudden withdrawal of the grip iron, and then their momen- 

 tum carries them forward to their proper place in the station. It will thus 

 be perceived that the intermediate traffic is by this means provided for with- 

 out causing any detention to the through-trade. 



The importance of this intermediate traffic may be inferred from the fact, 

 that in the year ending the 3Ist of December last, ont^of nearly 2,500,000 

 passengers conveyed during this period, nearly 1,000,000, or two-thirds of 

 the whole number, were derived from the short stations ; any system, there- 

 fore, which did not completely provide for this traffic, it is clear could not 

 under any circumstance he introduced with propriety on^this railway. 



To meet the case, it has been suggested, in the event of the atmospheric 



principle being adopted, that more frequent trains than at present should 



proceed from each end, and stop alternately at the intermediate stations, so 



that this important element of revenue might he accommodated. 



This suggestion was made in consequence of the necessitv of stopping the 



tlirongh-trains at each of these stations, as the system of separate carriages 

 could not conveniently be applied to this mode of traction. This plan, if 

 otherwise unobjectionable, it is obvious would afford a partial communication 

 between some of the intermediate stations. This, as far as it goes, is .in 

 advantage over the rope system, which only admits the intermediate stations 

 to communicate witli the termini. It is, howevtr, believed that this Iraflic 

 nould not be important, whilst it is of the utmost consequence to the culti- 

 vation of the intermediate intercourse that tlie intervals between the trains 

 at each station should not exceed a quarter of an hour. 



The average number of carriages in the terminal trains throughout the year 

 is four ; whilst in summer, to prevent the labour of having constantly to be 

 adding or taking carriages off, as many as seven or eight are continually in 

 motion, independent of the intermediate carriages. This great numlier of 

 carriages is requisite in consequence of the extremely fluctuating nature of 

 the traftie, which during the season is mainly derived from steam boats, 

 whose living freights, amounting occasionally to 400 or 500 passengers, have 

 frequently to be transported in one train. In the following eilculations, I 

 have, however, only assumed four carriages for the accommodation of the 

 terminal traffic, and two more for the intermediate traffic, v\hich though on 

 the whole larger than the former, is nevertheless more equally diffused. 

 Besides the above, the trains which stop at the Poplar station will be aug- 

 mented by one goods' truck, though at times two will be added. Thus the 

 trains will consist alternately of six or seven carriages constituting gross loads 

 of 100,000 lb. and 1 12,000 lb. respectively. I also assume the actual time of 

 stoppage at each station, independent of time lost in accelerating and re- 

 tarding the trains, at half a minute, except at Poplar, where I allow one 

 minute, as the goods' trucks would have to be pushed from a siding and 

 attached to the trains. Tlius, supposing the trains to stop alternately at 4 

 and 3 stations, the latter, however, embracing the Poplar station, the total 

 time of stoppage on the trip would be two minutes ; and assuming an ave- 

 rage velocity of 30 miles per hour were maintained, including the time lost in 

 accelerating and retarding at each stoppage, the actual time of travelling 

 would be 7i minutes ; thus the whole trip woidd occupy 9i minutes. 



But to accomplish this with oidy average trains woidd require a tube 2 

 feet in diameter, with a vacuum of 20 inches, and this on tlie far I her as- 

 sumption that a conductor was appropriated to each carriage, and that the 

 brake is applied to every wheel in the train, thus giving an adhesion of Jth 

 the gross load ; and further, that the brakes are applied with mathematical 

 accuracy. But with engines very far exceeding tlie power of the present 

 engines, the time required to exhaust this tube would he at least 6 minutes. 

 Thus the interval between the trains from the termini would be augmented 

 to 15^ minutes, or say |.hour intervals; that is, the same interval as is now 

 •illowed, but then the intermediate traffic would be subject to ^--hour intervals, 

 which I believe would reduce the traffic to less than half the present amount. 

 It has, however, been suggested that an average speed of 4(5 miles per hour 

 might be attained ; but with four intermediate stoppages, to accomplish this 

 would require a tractive force, independent of the great ordinary resistance 

 which has to be overcome at these high velocities, (as in this case a maximum 

 speed of 80 miles per hour is requisite,) equal to -J^th the gross load of the 

 train. This with only an average train would require tubes of a size and 

 engines of a power that would be entirely inadmissible. Seeing, therefore, 

 that with intermediate stations on a line of the extent of the London and 

 Blackwall Railway, very high velocities and trains of a greater frequency 

 than ]-hour intervals were unattainable, we may see what would happen by 

 adopting the existing engines with a pipe which, at a vacuum of 16 inches, 

 would be adequate to take a maximum load up the steepest gradients. 



This pipe would for a gross load of 225,000 lb., or lOO-J tons, require to 

 be 24 inches in diameter. Now, assuming as before the actual stoppage at 

 each station to be j minute, except at Poplar, which I assume to be for the 

 up-traiu 1 minute, but J minute only for the down train ; assuming also a 

 conductor on each carriage and the brake applied throughout the train, ob- 

 taining an adhesion therefore for retardation equal to j^th the gross weight of 

 the trains ; on the above data, together with the hypothesis of the engines at 

 each end working continually at their full power, I find that an average train 

 wdl occupy 16 minutes on the up and 16^ minutes on the down trip, whilst 

 a maximum train will occupy 22 minutes on the up and 20 minutes on the 

 down trip ; but as 5 minutes at least must he added for exhausting the lube 

 to 8 inches for starting, it is clear that trains at less than ^-hour intervals 

 could not be maintained on this line, especially when we consider that the 

 ■above times include no contingencies, which must frequently occur on a line 

 so worked ; as, for instance, in a London atmosphere the adhesion frequently 

 will not exceed -J^th the insistent weight : this alone, when it occurs, would 

 add 2 or 3 minutes to the trip, and as in the event of a train overshooting a 

 station it is impossible to move it back, the guards must commence applying 

 the brakes sooner than is indicated by calculation, in order to ensure avoid 

 ing such a dilemma. 



Unless, therefore, some expedient with which I at present am unacquainted 

 can be devised for obviating the necessity for stopping at each intermediate 

 station, it would appear that the trains could not be run more frequently 

 than at J -hour intervals with the engines now at work, thus reducing the 

 trains to one-half their present number, and this, too without effecting any 

 saving in the working expenses, inasmuch as there would be no reduction in 

 the staff of conductors, whilst the constant and severe breaking would in- 

 crease the cost of maintenance of way and carriages ; the wages of the rope, 

 meu also would not compensate for the extra cost arising from the engines 

 being kept continually at work, instead of for 10 minutes ODly out 'j every 



